a flush is not making a mistake. However, if you check and let him draw at his flush for free, you are giving him infinite odds on his draw (pot size: 0), which is far better for him than your charging him a bet for his draw. The situation is similar, but not quite as bad, if you call a bet rather than raising.
Note that typically you are both doing the correct thing. If there are players in the pot other than you and the flush draw, they are subsidizing both of you. Since you have the best hand, you have the most equity in the pot and benefit from every dollar that goes in. Your opponent with the flush draw is getting the correct pot odds (2:1) to draw. Everybody else is probably making a serious mistake, as it's likely they're drawing dead or near dead.
Remember, if you raise on the flop with your set, and half as many people call as would have called a single bet, you have gotten the same amount of money in the pot but you're competing with half as many opponents. Slowplaying is intended to let lesser hands catch up to a monster — and your set is not a monster (yet).
Was this article helpful?