I tend to save negative reps for people who stoop to over-the-top and pointless personal insults. And with the crowd we USED to have around here, that meant I was rarely handing out negs. More recently, I've been handing them out a bit more. Lotta newbies coming in here lately who think they can win name-calling contests with well-respected members who've been here for well over 2 years. Those clowns get negs from me, and their angry e-mails calling me a "fucktard" in response will go straight to my trash can with no reply.
Even had one guy try to retaliate by handing a neg right back to me. Just a quick note: the way the system on here works is that if you have a high reputation, it has more of an impact when you rep someone else. The opposite is also true: low rep = low impact. So, metaphorically speaking, I blasted him with a bazooka, and he fired back with a pea-shooter. Sound strategy, dude. If you really want to play that way, I'll trade negative reps with you all day, and we'll see who's left standing at sundown. Putz.
I try to give positive reps to any post that makes me nod in agreement, laugh out loud, or that I disagree with but that really gets me thinking. I used to hand those out a lot more. Lately? Not so much...
In the end it really doesn't matter. I like the fact that I happen to have a high rep, but I really don't feel any different than back when I only had one green square. But some people care about it a LOT, so there ya go.