I think they're a damn good idea. Most of them don't apply to people like myself, however, seeing as how I don't investigate crimes.
However, with some modification, they work pretty well. I'll add to this as I see fit/feel the need, but for now, here are The Rules.
1. Never trust a woman.
2. Never screw over your buddies.
3. Don't believe everything you're told. Double-check.
4. The best way to keep a secret is to keep it to yourself. Second best? Tell one other person--if you must. There is no third best.
5. Don't waste good. (Don't overuse compliments)
6. Never apologize- It's a sign of weakness.
7. Always be specific when you lie.
8. Never take anything for granted.
9. Have a knife whenever possible. A pistol is better. A rifle beats both.
10. Never allow anyone in your home that you wouldn't trust with a power of attorney, or at your side in a firefight.
11. Never date a co-worker. ("Don't fish from the company pier")
12. Never, ever involve a lawyer.
13. Never, EVER get married.
14. Don't cohabitate either.
15. Always be a team player.
16. If someone thinks they have the upper hand....break it!
17. It's better to seek forgiveness than to ask permission.
18. There is no such thing as coincidence.
19. If it seems like someone is out to get you, they are.
20. Clean up your own mess.
Yes, some of them are blatantly stolen word-for-word. Get over it. They work.