Hand 1: First, I would raise pre-flop, although I could see calling here if you think it's the only way you're going to get any action. Still, out of position I feel like calling is a weak play.

Second, the bet on the turn seems too small to me, as you're not really getting any information about his hand when he calls. I would bet at least 1 - 1.5x the pot here.

On the river, I guess a flush is possible, but based on the way the hand played out it's really tough for me to say what he might have. I think there's a chance he's simply put you on a weak hand and is thinking you'll fold to a little pressure. I would call and hope for the best.

Hand 2: Seems like an OK play to me. At these stakes, it's pretty likely that both of these guys have moved with something less than AA or KK, and one of them might even be in there with KQ, AQ, or worse, so you're probably getting the right odds to call.

Hand 3: This is probably one of those hands where there was no way the guy was going to put any more money in after the flop.

BTW, pocket kings would have made the nuts. you actually flopped the 2nd nuts..