Bush's comment about "Stuff happens" when talking about school shootings was initially seen as a potentially major gaffe. When the full context of the quote came out, though, it became clear that the two-word quote wasn't as dismissive as it seemed. Bush was talking about how a governor responds to many kinds of tragedies. Of course, Bush's choice of words could certainly have been better, and Colbert's choice to highlight them demonstrates why.
"The point is: Jeb Bush clearly has all the advantages that a candidate could want and should be doing way better," Colbert says. "But when he says things like that after 142 school shootings since Sandy Hook, it sounds like he's got -- how can I put this delicately -- 'stuff' for brains."