I have been know for making some really great calls. And I've also been known to make more than one incredible lay down. My weakness though, is in not being able to conceive of some of the hands that a bad player will not only play, but will call raises with, or the horrible calls they will make to chase improbable draws.
For instance, I'm holding K-K, looking at a J-3-K-7-5 board. I just can't imagine that my opponent could be holding 4-6 here. Not after I opened for 5x behind two limpers, making it 1000 to go pre-flop. I just can't conceive of someone that doesn't have a chip invested in the pot yet making that call with 4-6. Again, I can't see how someone calls 2000 with 4-6 after a K-J-3 flop. I just can't conceive it. When the guy is still there on the turn, I put him on something like a set of 3s or something like A-Q or Q-10. When a 5 falls on the river, I'm not even worried, even though I realize that card makes a straight for 4-6. I could see them holding 4-6 there if I had limped in or min raised, or tried to get tricky and checked on the flop. But this guy was calling off good sized bets with baby cards, with no pair and no draw on the flop. I just couldn't imagine doing that. To me it was just inconceivable.
But that's how I lose the biggest pots, when someone turns over a hand that I just can't conceive of.