He had some very interesting anecdotes to share from his time on SEINFELD. When he was first brought in as Frank Costanza, Larry David instructed him to play the part in a meek, wimpy manner, because he thought it would be funny to show it was clearly Estelle who wore the pants in the Costanza household. After spending a week being yelled and screamed at by Estelle, Stiller didn't know if he would survive in this role, and finally, during one rehearsal, he snapped:
ESTELLE: Georgie? Would you like some Jell-O?
FRANK: Why'd you put the bananas in there?
ESTELLE: George likes the bananas.
FRANK: SO LET HIM HAVE BANANAS ON THE SIDE!!
The entire crew busted out laughing, and thus, Frank Costanza was born.
He also mentioned on the evening of shooting that episode before the live audience, Jerry Seinfeld, Julia Louis-Dreyfus, Michael Richards, and Jason Alexander stood before him in a semi-circle, sort of protecting him from the audience before he was revealed as being part of the cast, saying he never before experienced such camaradery from other actors in his entire career before.