For me, the most important life lesson that I have learned is to laugh and smile a lot. It sounds really cheesy, and it kind of is, but ever a lot of my friends and coworkers have been asking me "jrod, why are you always so happy?" or "Dude, why is everything so funny?" to both of which I reply "I have nothing better to do than laugh and smile." Even on my worst of days, I still see the best in it.
What about you?