Alright, here's mine:

I hold a nice pair: say TT and do what I should preflop
if it's headup and flop is like AA4 or KK8 and I bet too much at it, I think. But of course 90% of the time the guy with trips is going to flat call this regardless of how big my bet is. So I get no info and end up either checkfolding to a possibly-worse hand or committing most of my remaining stack on the turn, with a fairly weak holding. Advice?

Second: boy, do I cave in to donkbets. Generally if I'm not beating two pair I just drop it to a donkbet of any substantial size.