A report happy is defined as someone who feels the need to report everything they deem unworthy of the webite, even if what they're reporting isn't against the rules. If they think it should be against the rules, they'll report it.
User: My friend is a pain in the butt.
Report Happy: You're going to get reported now. Profanity is against the rules.
User: I don't like you.
Report Happy: Reported for harassment!
Someone who reports you in a chatroom or similar, It can be understood if they do it for spamming or scamming, but they report for the tiniest little thing, even if it is not that bad, dangerous or if it was unintentional. Sometimes, after, or before reporting you, some of them like to rub it in/harrass you. Report happies are often trolls, bored users, stupid 12 year olds, or just plain assholes, usually with no life.
(on a RPG website in the glitch report section of the forum):
Guy in chatroom: Y'know, I just wanted to report a glitch on the site, you know, the webmaster was giving out special golden axes? Well I got one, I accidentaly clicked on the link again, and got a second one, is that normal?
Report Happy #1: lyk omg, you dumb ass! u wuz only suposed 2 git 1! now everybody on the fukin sight is gunna do dat! i'm am reporting you!
Report happy #2: yea, you retard, what fcking cunt. i'm reporting u too. way to expose the glitch.
Guy in chatroom: But, I didn't know...
Report Happy #3: what a waste of a 7 year account with premium and all items unlocked, and the strongest playable character... i reported him too. lol
Guy in chatroom: ...
(His account and all his years of hard work is deleted)...
...It later turns out that the site's staff has admitted it was an honest mistake, and for an apology, they let everyone keep the second item they got.