. >> when tim conway came on his goal in life was to destroy harvey. tist with his very first patient. we used to have a pool back stage, not as to whether harvey was going to break up, but how far he could get along in the sketch before he broke up. >> novocaine. okay here. novocaine. take a firm hold of the hypodermic needle. right. >> they never knew what he was going to do. but they knew it was not going to be what they expected. >> when they did the dentist sketch none of that was rehearsed. >> yeah, be right with you. >> poor harvey was helpless, tears coming down. and tim swears that harvey wet his pants during that sketch. >> i don't know why that worked so well. watching two actors break character and just crack each other up should not be as entertaining, but somehow when it's tim conway and harvey korman doing it, i could watch that stuff forever. >> i just thought if we have fun, the audience will. we're going to go out there and do what we do best, and it worked. >> you can plan it and write it and rehearse it. but you hope for some magic.