Stumpy's the same. She rolls around purring, and the vet tries holding her nose, which doesn't work, so she takes Stumpy to the sink, and runs the water fast to try and "scare" her and make her stop purring, but that never works either.
Shadow will sit and purr, Dianna will sit but be all tense, Holly is really relaxed but wont purr . . Then there is Annie which my vet and the techs have named "the cat from hell" She will hiss - spit - and bite unless "Daddy" is there. When she was spayed she did bit the vet tech - and so her nickname
How cute is that! Loki just sits there and blinks - he won't purr for the vet. Jacob growls! My sweet Whiskers (over the rainbow bridge) used to love one vet in particular (they had a number of them at the animal hospital) - he used to sing and rub up against her!