My grandmother dying when I was 4, my great-grandmother dying when I was 11, my parents getting divorced when I was 8, finding out that a close friend of mine had been hit by a truck when I was 10 (thankfully she survived), a friend of mine dying of cancer over winter break during 8th grade (that was truly horrible, she was at school the last day and seemed fine and then when we came back 2 weeks later we found out that she had passed away)...and there are two other things that are truly terrible, but I REALLY don't want to go into...
I guess the one that comes to mind is 4th of july, 1996. We were going downtown to see the fireworks and my dad got drunk and told me that my mom wants a divorce and all this shit and my mom was blaming everything on my dad and calling him a prick and shit cause he lost the keys and we were stranded downtown and they were basically at eachothers throats all night.
On the way back home my dad was accusing my mom of cheating with the neighbor and all sorts of mean shit like that and she was just ignoring him. So when we got home he got on his bicycle and road off and eventually came home in a police car. My neighbor saw how my dad was treating my mom and they got in a fight. My dad got his ass kicked and the cops came again, this time taking them both to jail.
It's a pretty ****ed up 4th of july story but it has a happy ending - my parents split up (thank god), my dad quit drinking and smoking pot, my mom and my old neighbor (current stepdad) actually did start dating and eventually had a kid (my younger brother). Ever since that night everything's been better. So basically it was the worst and best night of my life.