|img source: http://www.ebay.com/bhp/charlie-sheen-winning-shirt|
Because, when a team works well, the goal shifts from those internal improvements to achieving external marks of success. The bar is pre-set, if you think you're any good at what you do- your new job is to prove it, then raise the bar, and prove it again.
Nobody is going to tell you to work hard.
If your team isn't winning, train and then join one that is, and be elevated and changed by it.
If you're content with being a spectator in your field, or sharing your destiny with people who don't strive for excellence, you will never know the glory of the game, and I promise you'll have missed something truly great.