With anonymous rep you can't get pissy little PM's when you give negative rep...like this little gem I got back in January...
Last time I posted this PM I think it was in the thread where people actually were believing him about going to Pennsylvania to get psychiatric treatment from army doctors or some bullshit, and they were all sympathetic and supportive.The thread was removed shortly after.
Exactly my point. Ironically it also prevents some psychopath from putting you on their grudge list should you give them negative rep.
One of the reasons I rarely give it out.