A man walks into a bar and orders a drink. Then another. Then another.

This joke is a perfect example of misdirection (Review) and absurdity. The classic setup of a man drinking his sorrows away at a bar leads us to expect a genuinely tragic reason for his despair. We anticipate a story about a lost job, a failed marriage, or some other serious life catastrophe. The punchline completely subverts this expectation by revealing a "problem" that is not only mundane but also a source of joy for most people. The humor lies in the ridiculously outsized reaction the man has to a simple, everyday fact of his life.

The gag also hinges on some delightful wordplay that creates a momentary, nonsensical paradox. The statement about an oldest son also being the youngest son scrambles the listener's brain for a second. This confusion is immediately resolved by the revelation of twins, making the man's dramatic meltdown even funnier. It taps into the relatable trope of the overwhelmed new parent, so sleep-deprived and stressed that they can turn a basic piece of information into a world-ending crisis worthy of a triple whiskey.