A series of assumptions that start with "I think" which is twisted to "it's a fact".
When an uneducated opinion starts with "I don't think he's a racist" and turns to fact, "I know for a fact that he's not a racist". Then it's time to label the offending fucktard a "Stumble-fuck".
a game in which consists of selecting three random candidates, supplied by stumbleupon.com (babes section), where players must place each candidate into a separate category of kill, fuck, or marry.
"Hey John you want to play Stumble-A-Fuck"
"Yea lets pull up some hot bitches"
To be so bored at work that you load StumbleUpon, click on it incessantly all day long viewing random web pages until you run out of suggested StumbleUpon pages to display.