The thing about the guest spots on Cheers vs Seinfeld, is that the Cheers ones were memorable, but none ever became iconic. None will surpass The Soup Nazi, but there are so many more (one timers and recurring characters) ... Puddy, Mr. Peterson, Steinbrenner, Poppy, Bubble Boy, Banya, Bookman, Izzy Mandelbaum, Man Hands, The Close Talker, The Soft Talker, The High Talker, Pam, Uncle Leo, Crazy Joe Devola, Donna Chang, The Jimmy... the list goes on - not to mention all the girlfriends of George and Jerry. It wasn't always the character themselves, but the way they were used... hell, we never even saw Bubble Boy or Man Hands.