1) Jack Bauer is tough.
2) You can never be 100% sure who you can trust.
3) Sometimes you have no choice but to trust someone because they have the power (no matter how much you don't want him to)
4) Despite the fact that CTU is supposedly a highly secretive government agency, they find themselves with a lot of security risks.
5) There is always a mole.
6) The mole is always a double agent.
8) Life can always be viewed from multiple angles.