If you haven’t heard, MC Hammer is angry at Jay-Z for doing something truly heinous: dropping a few lines about Hammer’s bankruptcy. Apparently, mentioning a real-life event that happened 20 years ago is cause for aggression and exercise videos. Some say Hammer overreacted. Others don’t care. Either way, Hammer’s butthurt response is only one in a long list of rappers that have spazzed out over harmless bars.