As usual, it depends on the boots, the shorts and the person wearing them both. In my 20's, black shorts, black tights and black Doc Martin boots was my standard club wear. Uggs are generally ugly on everyone. It doesn't compliment anything you wear.
I guess I had a totally different look in my mind when I saw this because I saw this Korean Music festival thing on tv recently. One of the groups had a shorts+boots outfits that I thought was cute, but maybe they're more stage looks than normal people looks?
This was another boots + shorts picture I found while trying to find the outfit of the girls above.
But it's a completely different "boot" look than the ugg's