Forum rep is dumb.
As of this moment I am sitting at 1372, about 331 of which i got in about 2 days from posting a "clever" one liner reply to a thread.
I think for me forum rep is reason to laugh when you get a ton of rep for something stupid, or to see that people appreciate something you did (like write a guide or make an awesome post about forum rep)
Most of all, it lets me laugh at people who have super high greenies and think they are better than others because of that, as I will not be accused of being jealous by the pricks because my green bar ain't that big (where as it is pretty big right now surprisingly).....
Also I have never reported a neg rep, I just don't think it is worth it.