My go-to joke when put on the spot

Here's my go-to joke when put on the spot. Submit yours in the comments!

One day a Bear walks into a pub. He walks up to the bar, sits down and says to the bartender "Gimme a beer!".
The bartender looks up and says to the Bear "I don't serve Beer to Big Bears in my Bar in Boston."
The Bear asks again "Gimme a beer!!"
The bartender says "I told you, I don't server Beer to Big Bears in my Bar in Boston."
The Bear now evidently frustrated says to the barkeep "Look mate, if you don't give me a Beer I'm gonna eat that woman at the end of the bar!"
The bartender sighs and says "I don't serve Beer to Big Bears in my Bar in Boston!"
So the Bear stands up, walks to the end of the bar, grabs the woman, swallows her whole and then walks back to the barkeep and says "I bloody told you I'd eat her! Now gimme a beer!!"
The barkeep shakes his head and says "I don't serve Beer to Big Drug taking Bears in my Bar in Boston."
The Bear gasps in surprise and says "I don't take drugs!?"
The barkeep looks to the end of the bar and says "Well that's the Barbiturate."