Well, they're supposed to look out for you and have good advice when things go wrong. My dad usually goes with "so this is how I screwed up so you don't have to".

Sometimes where you get that can be a little unexpected though. My grandfather wasn't really a parent to my mom... actually, he caused a lot of problems. But Grandpa, the one who actually raised her even though they weren't related, he was always there for her. And that's what parents are supposed to do.