[Xhad]

This seems exactly backwards to me.

When you know you're hand is good, you're getting the pot either way, so you're more likely to be annoyed that your opponent is taking a long time. How many times in a low-limit live game have you seen someone say, "Here, I'll make it easy for you," and then table the nuts just to end the hand and get on to the next one?

On the other hand, bluffers are paranoid that anything they do will result in a call. Especially rushing their opponents since people frequently think a long time before talking themselves into folding. You just want them to fold, you don't care how long they take to do it. So genuine impatience would seem more likely to be the result of a monster.