I don't slowplay much because it runs so contrary to my aggressive image that it is a big red flag for my regular opponents when I do it. Sometimes I find spots that feel right for a slowplay, though...but then, I'll often look back and see that I would have gotten more playing the hand straight up.
Case in point:
At SLP, I call a standard raise from Jay with 77, and the flop comes Q78, two hearts. Jay bets 7, and I smooth call. I'm hoping for a non-heart, figuring Jay will continue his aggression with any real hand if the turn isn't a scare card. The Ac comes off.
Jay bets 23, with about 45-50 behind.
I'm now thinking that ace is either going to get me all his chips or allow him to get away. I put him all in to find out which, and after much deliberation, he folds.
Later, he tells me he has kings. Now, if I raise his 7 to 20 on that flop, I think he's going to repop, probably for all his chips. Instead, I let a scare card come that gets him off the hook. It turns out in this case, there were basically 15 scare cards, with all the hearts, any A and any Q being potential action killers. Two cards stack me instead of him. However, I don't know that aces or queens are action killers. For all I know, they are gin cards for me, giving him a worse hand he can't possibly lay down for 40+ more chips.
I was at least correct that he would continue his aggression on the turn if he had a real hand and a heart didn't come (and maybe even if it did). If he doesn't have a real hand, none of this matters because he's going to be done with the hand as soon as his flop bet doesn't buy the pot.
I hate looking back and seeing that straightforward play would have netted me more than trickery, but I don't want to be all ROT-y and decide that I shouldn't have smooth called the flop because of the results. When you hit a flop like that, in position against an aggressive player, do you like the raise or the smooth call? If you like a mix, what kind of mix, and what factors send you in one direction or the other?