My humble opinions are as follows:

Hand 1) Nothing you can do here. You have the temp nuts with a marginal draw to a better straight. The board was rainbow. Unfortunately for you, the idiot trying to go broke with A-A-x-x gave the guy with a set great odds to coup along. Reload!

Hand 2) Same deal. You have very tenous nuts on the flop. You really want to take it down here. You have to fear any card that doesnt hit one of your redraws.

Hand 3) I don't really like the reraise. You have given away the identity of two of your cards out of position, which is never a good thing. At these stakes, you will only very rarely push someone out of a pot with a reraise that small, no matter how crappy their cards.

Hand 4) This happens all the time if you are in the habit of betting top two. Get used to it!