Well, at the height of his jackassness, it seems that William Shatner would head out to Star Trek conventions and pick up chicks. So basically he was kind of lazy and didn't want to hear the word no. Well it turns out that even though it was easy and plentiful and that he was a "rock star" at conventions, he still wasn't happy.
"Admittedly, there were times when the woman I was with said: 'So this is what it's like to be in bed with Captain Kirk.' That was definitely a downer, in every sense of the word."