4. Tony Allen
Basketball players like to show off. We all know that. But somebody, somewhere needed to tell Boston Celtics guard Allen that there’s a time and a place for everything. In January 2007, Allen was on the floor playing in the final minutes of a big Boston loss to the Indiana Pacers. The referee blew the whistle, and Allen went to the hoop to throw down an impressive dunk. Of course, when he landed following his meaningless basket, he came down awkwardly and wound up blowing out both the ACL and MCL in his knee. Whoops. Fortunately for him, it didn’t wind up being a career ending injury, as Allen did see action for the Celtics in 2007-08 — which officially makes it okay for all of us to point and laugh at the sheer stupidity of his pointless display of machismo.