Okay. First off, I don't hate anyone. I could probably be buds with Hitler, though I'm not sure he'd be buds with me.
But some people do annoy me.
I made a MLP fangame a little less than a year ago. It was a great learning experience, but alas, too ambitious a project + full of humongous development mistakes meaning I essentially needed to start all over. I did get a demo out that showed off my gameplay though, and a small group of people who liked it.
Yes, I got my first annoying fan.
This guy made himself my unofficial bugtester. For a game that's mostly cancelled, at least for the stuff he's testing. He knows this; I posted a nice big "sorry but this is on hiatus indefinitely" message. I borrowed a friend of mine's forum to host everything related to the game, and he's been essentially spamming topics and sending me lots of private messages. Eventually I just ignored him, hoping he'd go away. No dice.
Now I do realize it's half my fault. I should say something rather than just giving him silence. I tend to run away from uncomfortable situations rather than dealing with them; it's a character flaw of mine I'm working on. I'm going to give him a nicely worded "go away" right after this, with some apologies for not replying to him. But that doesn't excuse bugging my friends asking where I am. Nor filling my inbox with PMs.
Passionate fans are great. I appreciate that he likes the game and wants it to continue. Honored, even. Were I a professional game designer I'd probably want a few fans like him to keep my ass in gear and my head out of the clouds. As a professional game designer though, I'd have a real place for people to post feedback, not just a buddy's personal forum. I could keep the rabid fans at bay without them intruding nor me having to put my foot down.
TL;DR: If you're going to send me lots of private messages, make sure they're naughty friendly and concise, not "hey why haven't you replied to me."