There's a few types of high-PE posters:
Some post b/c if you do good, you want to say it!
Some want to motivate/feel it's a team activity/community, still a positive reason to post.
Some want to be mentors, and mentoring improves your own game and feels good.
Some want to brag and be called out to argue.
Some, I'm convinced, are involved with forums/mTurk/RQSTRS somehow, as motivation.
Some are just plain lying.
Don't compare yourself to others, but by all means sometimes feed the trolls (a bare hook).