Rule #27: Two ways to follow: First way, they never notice you, Second way, they only notice you. (Season 7, Episode 15)

Never mess with a Marine's coffee if you want to live. (Season 2, Episode 9)

Rule #23

Never, ever bother Gibbs in interrogation. (Season 4, Episode 10)

Rule #22

It's better to seek forgiveness than ask permission. (Season 3, Episode 4)

Rule #18

If someone thinks they have the upper-hand, break it. (Season 8, Episode 24)

Rule #16

Always work as a team. (Season 5, Episode 5)

Rule #15

Bend the line, don't break it. (Season 11, Episode 4)

Rule #14

Never, ever involve a lawyer. (Season 6, Episode 7; Gibbs is said to have other rules involving lawyers, but according to Tony, this is the "umbrella" one)

Rule #13

Never date a coworker. (Season 1, Episode 15, and referenced on other occasions)

Rule #12

When the job is done, walk away. (Season 6, Episode 24)

Rule #11

Never get personally involved on a case. (Season 7, Episode 21)

Rule #10

Never go anywhere without a knife. (Season 1, Episode 13)

Rule #9

NCIS Quotes

McGee: Rule number 70 - keep digging till you hit bottom.
Abby: McGee! There is no rule 70.
McGee: Well, I--
Abby: You just made up a rule. This McGibbs thing has really gone to your head. I don't even recognize you right now.

Well tie me up and call me Loretta.

Fornell