I personally think the outfits on most pets are pretty hideous and I secretly judge you if you dress your pets up on a regular basis. On the other hand, I love Halloween costume photos of people and their pets. Most of the time, the animals don't look uncomfortable and some of them even look like they're happy (from all the extra attention, I'm guessing, plus their owners probably sound happy and excited). I'm also guilty of putting a little santa hat on my cat for Christmas. He hates it and takes it off within the next minute and we usually let him be after that, so I promise I'm not torturing him too much.
I agree, in the summer, it doesn't sound like a good idea to put extra layers on your pet when they need to sweat. Like other posters have said, it all depends on the pet.
