Before the Trouble Starts

A guy walks into a bar and says to the bartender, "Give me a beer before the trouble starts."

The Bartender hands him a beer, the guy skulls it and says again, "Give me a beer before the trouble starts."

The bartender hands him another beer and the again the guy skulls it and says again, "Give me a beer before the trouble starts."

The bartender hands him another beer and the guy skulls it again. "Hang on," says the bartender, "how are you going to pay for all of this beer?" The guy replies, "OK, now the troubles started."