I'm not quitting parkour just the site
So you think just because you're not as helpful as others you're useless? That's stupid. If you knew any better, but you don't, that you ARE useful.
A group of ten people live together, everybody has a job except the last person, because she is a parapalegic. The other nine leave to do their jobs while she is left to do nothing. She assumes house-keeping while the others are out.
Point being you're not not helpful. I'm not always helpful, in fact I enjoy trolling with consistency time and time again, I also enjoy being an asshole. You think you're not helping now you won't be helping at all if you leave.