It wasn't anger, it was a seizure.
Elaine: Hey, hey, wait a minute! Let me ask you something. Kramer, the last time you hit your head, was Mary Hart on TV?
Kramer: Yeah.
Elaine: That is it!
Kramer: What?
Elaine: That is it! Mary Hart's voice, don't you see? There's something about Mary Hart's voice that's giving you seizures. Just like, just like, just like that woman in Albany!
It could be the jimmy-legs.