walk-into-a-bar

Which of these "walk into a bar" jokes do you find the funniest?

• A mobius strip walks into a bar sobbing. The bartender asks, "What's wrong?". It replies, "Where do I even begin?!"~
• Infinitely many mathematicians walk into a bar. The first says, "I'll have a beer." The second says, "I'll have half a beer." The third says, "I'll have a quarter of a beer." The bartender cuts off the fourth mathematician and gives them all just two beers, saying, "I'll save you some time -- we enforce limits here."~
• Two men walk into a bar. The third one ducks.~
• E flat walks into a bar. The bartender says, "Sorry, we don't serve minors."~
• These are all terrible, and my day is ruined.~