I feel the need to pass on some of my recently-acquired knowledge about dogs:
Tail-wagging does not necessarily imply happiness. When a dog wags its tail it is excited about something: so it could be frightened but excited (which is why some tail wagging dogs could still bite), curious but excited, and yes, could also be happy and excited.
So I think pugs are still fine. Even though they're bred silly. :)
That was my know-it-all comment of the day, feel free to ignore.
(If this was posted twice somewhere, I still suck at the buttons here. My apologies.)