I think it's good for a person to accept that they might not be THE BEST OMG at everything (or anything) but they should still try their best at the things they can find personal fulfillment in.    It's dumb for someone to quit a football team because they're not the quarterback and it's stupid for someone to quit playing an instrument because they're not first chair in their section. The same can be true at a job: a person might not be an expert at something, but they have a role to fill and they should do that role to to the best of their abilities.