I
dogs of all breeds. Cats, now that's a different story. Yes, I have met dogs that I don't like, but it's never been because of their breed or appearance. I'm not very judgemental when it comes to looks, that goes for both animals and people. Personality is what counts. Otherwise, I wouldn't have that snorting, bug-eyed and smooshed face Pug in my avatar.
I've never really known a shi-tzu, so I can't comment specifically on them.