I try not to let post counts do anything for me. I'm happy with mine, I have no particular goals to bring it any higher. I don't much care for post counts. When I see someone with a very low post count, I'll tend not to think much of them because it's very possible that they just stop coming here all together. I'm sure a lot of users sign up, maybe come around for the first week and post about 10 times, and forget about this place. Once you start seeing the post counts get up into the 50s and 100s then I can guess that the person is genuinely interested in contributing to PC. Oh, and if their posts are well written, thought-out and explain a valid point, that never hurts.
I tend to care a lot about my posts. If I start writing one and I don't see myself getting anywhere with it, I'll just drop it. I hardly post anywhere where I don't think the topic is worth the time it takes to reply. I know that makes me sound kinda pretentious lol but it's the truth. I won't bother with an uninteresting topic.