What occupation did George always want to have?
George always wanted to pretend to be an architect [The Stakeout]. He once pretended to be a marine biologist [The Marine Biologist] because Jerry told their friend from college that was what George did for a living, so he had to play the part. George was talking to Jerry, earlier in the episode, about the TV show he saw about whales and mentioned how fascinating it was. That’s probably why Jerry blurted out marine biologist when the old friend asked about George.