argh. I decided to play a hand I don't usually play, A-2 suited, and low and behold I flopped the nut flush. I decide to slow play and the one other player goes along, betting and letting me call every bet.
After the river, having not really even looked at the rest of the board because I thought I had the nuts, I raise $100 and he pushes all in. I of course call and now we both have $200 in the pot.
What I didn't notice was the board had two pair on it, QQ and 99. He turns over a QK and announces "Full House" and takes down my money..
It was greed that caused me to let it go to the river, and stupidity that I didn't notice the possible full house.