one pair on showdown in pt

[lunapark]

Looking at one of the stats post it showed he was a pretty big winner when he had a pair on showdown in PT. I'm just curious if most players here are winning money with a pair....if so this is probably a pretty big leak for me.
On that note how often are you folding top pair or an overpair before the river on a not too ridiculous board (4 to a straight or flush).

If the a third flush card comes on the river and you are raised by a fairly aggressive player (who you have seen bluff raise the river before) are you folding to a raise or are you calling in what is now a pretty large pot?