Hands that don't bother me when I lose and have a suspicion I am beat when I call:
my KK vs. AA
my set vs. over set
my boat vs. quads

Actually all three of these scenarios happened to me in the last 6 hours of play but I still ended up with large profits. I think I should keep track of each allin when holding 2nd nuts to see how often I win. I'm fairly sure the donk allins vs. those hands far surpasses the ones I lose but I don't have hard evidence.