Eminem. Never has trash to straight up mediocrity been celebrated more. You can complain about Radiohead all you want, if you deny they have at least a couple amazing albums you're a fucking idiot. You can hand wring over RHCP, Rush, Tool, etc yet for the most part they have at least one great album that stands the test of time. Can you say that about Eminem? All of his best material has aged like shit, especially when compared to actual classic hip hop albums. If I throw on Illmatic or Death Certificate today, is anyone going to be like "nah, this isn't cool anymore"? No, and if so you're a plebe bro.
Marshal Mathers LP is a good album, I'm not denying that. But the initial level of shock and amazement wore off a decade ago. It's now just a crass album full of very basic, lifeless production and wack guest appearances. There is no funk or soul or swing or whatever you want to call it.
Technically Eminem was a great rapper. But so was Canibus. Ultimately both have been trash for longer than they've been good for the same reason. You can only rap about rap for so long, you can only rely on your flow for so long, and you can only do corny shit for so long. Eminem is a 40 year old man rapping about eating buggers and raping chicks. Come on. His artistic growth arc has pretty much been...nothing. I'll give him props for making nice with his mom, but outside of that it's the same shit he rapped about 15 years ago, minus the dope flow. Now his flow is trash.
Annoying fans? How about fans who don't listen to anything outside of Eminem, waxing poetic about how he's the greatest rapper ever, the only rapper who doesn't rap about violence (lol) and drugs (LOL) or street life. At least Radiohead fans tend to have a college degree.