My mom kept me from my father's side of the family a little extra when I was a kid, and I ended up not being as close to them as I'd like. While I can understand why to an extent (my parents did NOT divorce on good terms), I didn't get to know my grandfather while he was still in his proper faculties.
I'm fairly certain I've talked about this before, but it's something that's always stuck in my craw, so to speak.