This isn't a good joke.
Nothing.
One plays hard rock, the other is rock hard.
One baits his hook the other hates his book.
Clickbait.
Three. One to post it, the second to post a better punchline in the comments, and the third to complain that it's a repost.
Timing.
That you clicked on this link only to correct my grammer....
Give me the gif of it.