When I see a guy on the street with a swastika on his armband and he's goose-stepping and shouting "Heil Hitler", I automatically assume that he's a Nazi.
When I see a guy with a Confederate Battle Flag in his front yard on race days together with a huge pennant of a race car driver, I automatically assume that he's a NASCAR enthusiast.
When I see a guy driving a Hummer, I think to myself "that's probably a douchebag."
When someone says they were listening to or watching Limbaugh or Hannity or any of their ilk, I assume that I'm dealing with a dumbass.
These assumptions have never failed me yet.