This thread shall become a repository for wisdom to benefit our entire community.
Please post things that you know, as in the stuff you learned the hard way, that really sucked, that you could spare other people the hassle of dealing with if someone were nice enough to share their wisdom in a post like this...
Here's a few of my faves:
(1) Don't ever buy an extended warranty for anything, you will never get a damn thing out of it. Think about it. You pay monthly premiums for years to cover an item that will likely be twice as powerful and half the cost when yours breaks. Even with big ticket items like cars, you'll get shite out of them. They'll tell you that they cover 2-3 little things, but the rest is on you. Insurance companies are one of the four horsemen, believe it.
(2) Life's too short to take shit. Don't ever let anyone emotionally or physically abuse you. Fight back or escape, but don't take shit. If you do, then you will likely fall into having a victim complex and unintentionally allow people to walk all over you for many years of your life. Stand up for yourself. Tell the people that wrong you, or say hurtful things to you, or threaten you to go fuck themselves. I can't speak for everyone, but I know I'd rather get my ass kicked and retain my dignity than let anyone treat me like shit or abuse me.
(3) Take the time to formulate short term (1 year or less), mid-range (2-5 years), and long-term (further than 5 years away) goals for yourself. Plot a journey for your life. Guess what? The actual course of your trip will not be exactly as you planned it. BUT - I guarantee you that the life journey of someone who has taken the time to envision their future, and work toward it with realistic, incremental, and attainable goals, will be far more rewarding and interesting than the roadmap of a life that has just been allowed to pass by with whatever the winds blow into it.
Who's going next?