Awkward
That awkward moment when think you know what the other people around you are talking about but come to find out you are totally wrong.
Example:
person #1: what the heck was all that about last night?
you: yeah dude your mom was a total bitch
person #1: umm we were acctually talking about Jersy Shore!!
you: ohhhhh
person #1: asshole (under breath) *as they role their eyes*