Hey John, how are you going?
Helium, yeah good, what about you?
(Hey Liam)
Hey John, how are you going?
Helium, yeah good, what about you?
(Hey Liam)
Listen up, buttercup. The joke is that the dude thinks his friend John says "Helium" (He Liam) instead of saying that he's doing well. Get it? 'Cause helium is a gas and people's voices go all squeaky when they breathe it in! And you probably huffed some helium as a kid, judging by your inability to grasp simple jokes.