Things that puzzle us:
1. In Yankee White it says Gibbs has been in NCIS for 19 years but later it is reduced to 16 years. <Is this a misfire? He started with NIS.><or could he have just been referring to interrogations? Did he do that in the Corps?>

2. Gibbs' time at NCIS is tardis-like: the years hold more time on the inside than they appear to on the outside. Gibbs, in 16 years, has been trained up by Mike, become Jen's trainer and worked with her in Paris. Done 14 months in Moscow with second wife. (so where did first wife fit in and how soon after Shannon's death did Gibbs remarry?). Then back to Washington to do 7 years with Tony's predecessor, then 2 years with Tony, then the show starts in 2003. Along the way, Gibbs and Ducky work with Jenny in France, Gibbs and Jenny do work in Serbia, and when Jenny takes up the Directorship, it is only 6 years since Gibbs and she were together (Kill Ari, season 3 start). It is a quantum canon: time in non-linear progression.

3. During the early episodes of season 1, Tony doesn't know who Shane is and it's explained to him (giving the appearance of not having any movie knowledge) then as the season and series has progressed, he's got a deep knowledge of movies and it's trivia.

4. In Yankee White, the Secret Service agent calls Fornell "Tom" when speaking to him on the cellphone. It is later established during the series that Fornell's first name is Tobias.

5. Speaking of Tobias...early on, Gibbs and Tobias don't know each other, however as the series has progressed, it turns out that they share an ex-wife (not me!) and something of a history that was never hinted at early in the series. <Maybe the marriage occurs between "Yankee White" and "Twilight">

6. Rule #1 Changed from "Never let suspects stay together" in "Yankee White" to "Never screw over your partner" in the fourth season.

7. Rule #3 Changed from "Never believe what you're told, double check" to "Never be unreachable"
nb. which holds no water cos Gibbs leaves his cell behind all the time =]

8. Sometimes Ziva keeps kosher, and sometimes she doesn't.

9. The first two seasons, Abby occasionally mentioned wanting an assistant, then, when Chip shows up, she hates having one.

10. Version 1: In Yankee White when the terrorist lets fly with a round from the AK-47 he does not puncture the plane's fuselage or hit Gibbs. According to a former military pilot of my acquaintance, firing a round from an automatic weapon inside a plane would cause the fuselage to rupture and explosive decompression to occur. The whole side of the plane would blow out.... leaving Gibbs and anyone else in the vicinity free-falling 40,000 feet to their deaths. An Aloha 737 suffered a catastrophic decompression that took half the roof off, and that was only corrosion. Not only would Gibbs have been sucked out, you'd do your port inner engine at least, probably the port outer as well, plane would swing in toward the dead engines, and if the pilot didn't get on it quick (opposite aileron, trim out and descend, declare an emergency and get the thing down!) you probably have plane debris all over the countryside~!

Version 2: It was not an AK-47 but an MP5 weapon which could use 9mm low-velocity anti-personnel bullets specifically intended for use in places such as Air Force 1 plane, where you want to stop people but not damage the plane. (see the Threads, below, for an explanation). So it is not necessarily a misfired canon...

11. In the season 1 episode "High Seas" the urine samples of the sailors are all uniformly the same dark golden colour, indicating a massive breakout of UTI on the Lady E. (or a failure to adequately hydrate...water water everywhere, nor any drop to drink...)

12. When Gibbs first meets Ziva, he mentions the bunked assassination that ended the "Munich" assassinations. He said that the waiter was Palestinian when he was Moroccan, according to Discovery.

13. Michael Weatherly's cringe-invoking Aussie accent in "Seadog". He managed to sound like every bad Paul Hogan impersonation you've ever heard.

14. DiNozzo's so-called fluency in Spanish sounds like somebody who's just swallowed a bad tourist easy conversation book - even Bush's brother has a better Spanish pronunciation!

15. Gibbs and Ducky have supposedly only known each other 10 years, but one seems to get the hint from the dialogues, that we're supposed to think they've known each other considerably longer.

16. Ducky's mother remains 95.

17. In Season 1 or 2 (can't remember which), Ducky talks about having several nephews and nieces and some siblings, in later seasons he's said to be an only child

18. In 1x09, "Marine Down," Tony puts two 9mm holes in his black NCIS cap at the shooting range. Later in this episode, he gives the hat to Abby, who finds it cool. In 3x04, "The Silver War," what we assume to be the same hat is now in the possession of Ziva, who is told by Gibbs that the holes are for ventilation.

19. In 1x02, "Hung Out to Dry," when Tony enters GIbbs's basement, he behaves as though he's never seen Gibbs's boat before, nor knew anything about it. However, in 1x10, "Left for Dead," it's revealed that Tony has actually stayed at Gibbs's house before, "six months ago," which would have been long before the events in 1x01, "Yankee White." If Gibbs spends as much time on that boat as we are led to believe, Tony would have known about it from having stayed at Gibbs's house before.

20. In 1x23 "Reveille" McGee states that Ari Haswari's parents are Dr Benjamin Weinstein and Dr Hasmia Haswari. Then in Kill Ari Part 2 his father becomes Deputy Director David. Idea: Perhaps David was undercover with an assumed name. There was some discussion that he wanted to father an Arab child, to "grow" a double agent.

21. In Season 2's "SWAK" after the team is showered Gibbs is clearly wearing only the NCIS blue jumpsuit as his upper chest is bare... a few minutes later, not having been able to leave autopsy, he is now wearing a white undershirt under the jumpsuit.

22. In Sandblast, Col. Mann mentions to Tony that Gibbs has four ex-wives, (I bet negotiations aren't his strong suit). Later she knew nothing about Shannon or Kelly and had to twist Ducky's arm to get him to tell.

23. Season 3 episode 4 Switch Ziva, Tony and McGee get in a car in the lot then Tony says it is the wrong car he is standing with the door open leaning on the door. Then they cut to a shot of the row of cars and he is in the car with the door shut.

24. In Hiatus, season three when they are saying DiNozzo is acting like Gibbs, and the next thing he will be doing is drinking mass amounts of coffee; McGee tells Ziva that Tony does not like coffee, yet in an earlier episode, (season 2 , "Call of Silence"), DiNozzo stays at the home of a WW2 veteran, and when he wakes up in the morning, the first thing he asks for is coffee (after being offered an alcoholic beverage for breakfast).

25. In Season 1 episode 'One Shot, One Kill', Gibbs and DiNozzo have to search a derelict building. There is no electricity so they have to use flashlights.... but the elevator in the building is working!

26. In Season 1 episode 'Weak Link' Ducky says he couldn't sleep because of his noisy upstairs neighbours, yet in later episodes we discover he and his mother live in an elegant detached house. [Please note this is not true. Ducky refers to noisy neighbors but does not say they're located upstairs. Check the DVD at 0:33:34 into this episode. Thanks.]

27. In Season 4 episode 'Grace Period', when Ziva reads the Arabic script after the suspect is killed, her eyes travel from left to right, not right to left.

28. DiNozzo will usually mispronounce Norfolk as (nor-folk) but it really is (nor-fick).

29. There are no palm trees in Virginia Beach.

30. Ziva is suppose to be such a remarkable killing machine and she has stated that she has killed before, I can
not remember the title of the episode.. but when she has to kill the guy up close and personal she gets all
upset. I was watching this with my friend and even he said, "She should not be so upset, she has killed
before." I totally agreed with him. (possible solution: if you are talking about recoil in season 5, I think that she is upset about her almost dying due to her supposed bad judgment)

31. Jenny Shepard's hair- In Angel of Death it is still fairly short, but then in Bury Your Dead which is suppose to take place hours later than Angel of Death it is several inches longer. No one's hair grows that fast!

32. In Yankee White, the medical examiner says he is the Witchita County medical examiner- well if he is he traveled way out of his jurisdiction, because Witchita is in Sedgwick County!!!

33. In Yankee White, Air Force One lands at Mid-Contient Airport- not McConnell Air force base where they actually service air force one.

34. The hat- in Marine Down Tony shoots up his hat because Gibbs tapes it to the target, but in Silver War Ziva, asks why there is a nine-millimeter hole in her hat- NCIS does not shoot nine-mils. They shoot 40- caliber sigs.

35. In Bikini Wax, Tony says that he graduated from Ohio State in 1989. In SWAK he says it was 1992.

36. Why, oh why is there a soundboard with at least 24 channels in the booth for interrogation? How many mics are they using in there anyway?

37. In the episode Boxed In, Tony explains that real money burns orange, and proves the money in the crates in counterfit by burning some. It burns blue and then white. Later, when he throws some money out of the crate to show the bad guy, the money burns orange!

38. In "Kill Ari" ,after Abby gets shot at, Gibbs says he'll get her bullet proof glass but Abby tells him there's no such thing. However, in "One Shot, One Kill" a sniper shoots at Gibbs and the bullet gets stuck in the glass. There's no way it was not bullet proof, a sniper people!

39. In "Under Covers" when Ziva is on top of Tony you see Tony push all of Ziva's hair back but when she hits him, a piece of her hair falls down. When they show Ziva's face, all of her hair is pushed back! That was not done well!