This might be popular in many other fields, but I've heard this phrase used mostly in NASCAR circles.
If you're not cheating, you're not trying hard enough.
Such an unethical statement still seems to make a little sense. Obviously when competing, whether trying to win a championship or a contract, a person or a team will exhaust every possibility within the guidelines to win. But there always comes a point where brainstorming within the boundaries quickly gets stale. At that moment, compromise almost always enters the mind of the competitive and the driven. Even the most sanctified people may at least review their interpretation of the rules to see if an advantage can be gained. Others with a lower sense of integrity flat out disregard any regulation. Yet neither of the groups can be pinned with not trying. I mean, no one really listened to their teacher when she said it's not whether you win or lose but it's how you play the game, right? At least, not until you get caught.