You know the kind.. Not the horrible someone has died kind, but the less traumatic ones. The sort where something has happened. Something you weren't really happy about, but you seemed to cope with ok. Maybe you even wondered why everyone else makes such a big deal about it.
Eventually it wanders off to the back of your mind, and you forget it even happened.
Then you're just going about life.. let's say, taking a shower, and suddenly
THERE IT IS! With no idea what brought it into your mind, you stop everything, and just stand there thinking:
HOLY CRAP, I'M FORTY!!
HOW THE HELL DID THAT HAPPEN?!
Yeah... that just happened.