miscommunication (dramatic irony), the "I have no name" cliché in film (though not all clichés are bad), and really good counterfeiters (with whom I laugh with heartily)
Some things that makes me feel uncomfortable because other people are dense are:
when somebody flips because you talked about a real 21st century issue and provided examples (examples they somehow construe as an affront to their race/religion/identity)
when you realize that not only is x actually happening, but it's also far lamer than you thought would ever be possible
and when your 4.0 buddies repeatedly try hounding you into accepting that <$5 you loaned them for lunch
and, misnomers