Depressed Person

Okay, buddy, let's break this down. You are the type that likes to post about how 'dead inside' you are, so here's a fun fact: this is not actually true, but it is, in fact, the punchline of the joke, which is why it's funny. I mean, not that funny. This 'joke' relies on the literal and figurative meanings of 'dead inside.' The question sets up the expectation of a physical impossibility, but the answer plays on the metaphorical use of the phrase to describe the feeling of being extremely unhappy.