I give rep points or thanks when a post is really good(i.e. someone takes the time to type out a in depth response explaining something in reply to a question, someone answers in a particularly witty way, someone posts something unusual to share it with everyone). I very rarely will give neg points out, reserving that for only when someone is obviously being a jerk, nasty or trolling. I never give a neg point to someone because of a difference in opinion or because they don't agree with something I said, etc. You pretty much have to TRY to get me to give you a neg point, really.
I don't thank every single post on a thread of mine. I don't thank every picture posted. It's not that I don't enjoy those, or feel appreciated when people post on a thread. I just always thought of rep points as something to give for specially good postings, not just all the time.
This is only the way I feel about the system, not the way I think everyone should do it. I think that if someone is new and they are making a lot of good posts, they can rack up a lot of points fairly quickly. If a lot of newer members have started assigning points or thanks to every single post in a thread they've started, you'll see folks getting higher point totals.
Haha, I just looked at my own green boxes and it says "Wolfyhound can't wait to help you!". While that might not be true on my grumpy days, at least I try not to post nasty comments just because I'm having a bad day and am in pain. LOL.