He doesn't like dogs with squishy faces - spaniels are a big one, show type goldens, etc. Thinks they look dumb. I think the "soft" expression contributes to that, too.
Excessively hairy dogs. He doesn't dislike them really, just doesn't want to own/deal with it.
Asymmetrical dogs. It's an OCD thing I think - not to make light of OCD, I mean it's actually an issue for him, and not just in dogs. He deals with Rowan's spots because Rowan's already around, but definitely does not want to do so in the future. We both like Beezers, but I don't know if we'll ever have one because I don't know how to explain to a breeder that being symmetrical is important. Like... this dog would be fine:
This one would not:
I guess just be honest and say that as superficial as it sounds, I would only want a neatly Irish marked dog.
Otherwise he's pretty open, I guess... he likes everything from pugs to GSDs to wolfhounds. Not that he'd want to own every dog, but not other real dislikes.