what does this mean?? don't you WANT him to fill up against your str8flush?

I would guess he's happy that dude (who must
have the flush) won't be scared that he had a set and has filled up - now he has to lose pretty much his whole stack.

Also I agree that long term you're losing money fearing the str8 flush except in very special circumstances... some one posted here the other day when they had AKs, flopped the flush, a fourth comes out, str8 flush is possible, and they were getting re raised - Q was on the board, so the guy correctly guessed that his opp had to have the str8 flush. But unless you have all that info (top 3 flush cards accounted for) I think I'm paying this off most of the tme. Here the way you played it he could easily put you on a Ksuited hand.

vnh BTW. Had to be tempting to bet more on the river, but you made the right read and got paid.