Wrong side of the bar

A construction worker walks into a bar. He's a rather large, menacing guy. He orders a beer, chugs it back, and bellows, "All you guys on this side of the bar are a bunch of idiots!" A sudden silence descends.

After a moment he asks "Anyone got a problem with that?" The silence lengthens.

He then chugs back another beer and growls, "And all you guys on the other side of the bar are all scum!" Once again, the bar is silent.

He looks around belligerently and roars, "Anyone got a problem with that?" A lone man gets up from his stool unsteadily and starts to walk towards the man.

"You got a problem, buddy?"

"Oh no; I'm just on the wrong side of the bar."