If I'm around my house, I wear shorts with them. Fitted jeans look really nice with them, or even skinny jeans. It doesn't look good to leave your pants untucked, though. You can even wear sweatpants with them, as Uggs are a casual shoe. Basically, wear whatever you want. Brown works with anything. Just make sure to tuck the pant legs in:)
You should wear like a nice tan sweater with some blue jeans
The whole premise of the question is bad. Nobody should wear those UGGly shoes.
I don't know if it helps but I don't think you should. I personally think it looks really wrong.