As promised, a hand I won but misplayed...
The game is 2/5 NL. We have about 1200$ in front of us, covering the other players in the hand. We are in MP. A player limps in front of us. We look down and find JQs. We raise to 20. The button calls and so does the original limper.
The flop comes: 4h 7s 9s. The EP player checks. We check. The button checks.
Thoughts: This check is non-standard, certainly. Most players, with two overs and a flush draw, would bet out. Honestly, I couldn't tell you, now, why I decided to, but in the moment it felt like the right play. A small part was that the EP player had shown a tendency to play some aggro/tricky poker; I thought he was more than capable of check-raising a c-bet he perceived as weak. I also think that NOT betting a flush draw actually disguises your hand. Because everyone "knows" that "good" (by which we mean aggressive) players always bet their draws. But if you don't bet the draw, you will sometimes find it easier to get paid off when you hit the flush. Also, betting on a draw has value only if some of the time you can get people to fold without hitting your hand. And in this case, with two players who'd shown themselves to be fairly 'sticky', I thought that was unlikely. I could have bet here and it would have been fine, but I didn't. (This street was not the reason I think I misplayed the hand, btw).
Turn comes: 8s. EP checks. I bet 35$. The button calls. EP folds.
Thoughts: Clearly, with a Q-high flush, I have to start putting money in the pot. When the button calls, I assume he has a high spade (Ace or King, obviously) and is calling on a draw. The button, by the way, is a man in his mid-50s. He lives in Vegas and is clearly a regular at the Venetian Poker Room. That said, I'd guess he's a slight loser, lifetime, playing at this level. He hasn't shown a lot of imagination, and he shares a lot of the flaws of your standard 2/5 player; he overvalues medium-strength hands, he makes bad calls pre flop, and he bluffs in situations where it's obvious he's getting called. He's not by any means a donkey, but neither is someone we particularly fear.
The river: 6h. The board now reads: 4h 7s 9s 8s 6h.
I now check. I've been watching this player for a while, and I've noticed a tendency on his part to bet any river when checked to (he's used this play to pick up a number of pots where, my guess is, he does NOT have the best hand). So, the odds of him bluffing here aren't terrible. Recall, too, that my assumption, based on his betting so far, was that he was on a flush draw. If I lead out, betting into him, his missed flush draw will fold. However, if I check (representing, maybe, that I too was on a flush draw--remember what I said earlier: everyone assumes that everyone else will always bet their flush draws) there's some chance he might try to bluff me off my missed draw.
So, as noted, I check. He now bets 75$. And I make what I decide later is a real mistake. I call.
Why is this a mistake? What should I have done?
I'll wait for the inevitable deluge of comments from my legion of rapt readers before I post more.