When you get called on that flop, he usually has a flush draw. He may have a set. Two pair is less likely, but possible if he plays Q8. People have two pair more often on flops like JTx than Q8x.

I'm paying him off one small bet because small bets usually mean either really weak hands or really strong hands. Sometimes people will throw out a small bet in hopes you don't have anything and you'll go away. If he pots the turn I'd just fold.