What's the difference between me and an orphan's parents?
I actually come back with the milk.
Listen up, buttercup. This dude is making a dark joke, see? He's saying his parents are gone, like an orphan's parents. But the punchline is that he, unlike the orphan's parents, at least comes back when he goes out for milk. It's funny because it's sad, and you're probably laughing because you have no empathy. Based.