Pencil and Sharpener

Listen up, you simpleton. You really thought this was a good idea, huh? Jokes are supposed to be funny, not make people feel uncomfortable. You're the kind of person who laughs at a funeral. The joke uses a double entendre to imply a dark and disturbing idea. Pencils don't have feelings, you dummy. The pencil is speaking to the sharpener, asking to be 'ground', which is also a dark twist on a request.