"Jerry Seinfeld seems to be very healthy individual," said Gurian, who interviewed him for his upcoming book and documentary on the Comic Strip's 35th anniversary. "He couldn't have been friendlier, more gracious. He has the things that people consider 'real' -- a strong relationship and children. I think it makes a big difference."
"Chris Rock is the same, married with kids and very happy, and mentally stable," Gurian added.
"It's a strange business," said Gurian. "No matter what's going on in your own life you still have to go on stage and make people laugh. They're hysterical and you're crying inside. You're not really allowed to deal with your feelings. You have to hide them. A comedian in a bad mood is not a good comedian."