I completely agree about the importance of confidence. If you don't believe you can succeed, you might as well quit. I agree it sounds harsh, but there are so many aspects an athlete needs to be prepared for prior to taking the field, if part of their mental preparation is being hampered by doubt, they're already at a disadvantage. Also, attempting to play with a lack of confidence also gives the player a reason for not giving their full effort, which not only sets just themselves back but it sets the team back as well. I understand the negative stigma around being cocky, but you have to at least be confident!

Anyway, good post!