This will probably sound strange and/or conceited but I think my dad's birth/existence and mine are the most positive "events". My dad can be a massive asshole but he taught me how to fight for what I want and work hard. So I did and do. He improved my life over his by an indeterminable amount. I hope to do the same should I ever have a kid. But the amount he improved my life over his is insane. Sure, I grew up in a dysfunctional home but I never, ever wanted for food, entertainment, education, clothing, shelter, or even my parents' protection.
I hope my kid will grow up without the dysfunction I did - drinking, fighting, abuse. He could only strip out so much, I can strip out the next. In two generations we could wipe out the worst of his life and the worst of mine. I have hope.