"Expect Greatness" has been one of my favorite mottos for a long time. In high school, while playing football, I put that on the front of my playband. Not to tell everyone else to expect that just just from me, but to tell myself that it is my job to expect greatness from my teammates, my coaches, and especially the other team.
No good thing will ever come from underestimating yourself, your teammates/coworkers, your coaches/leaders, or your competitors/opposition (i'll let you handle the relating from here). Think about it, you can't control what others do. Sure, you can guide, motivate, and inspire, but the decision still lies with them to rise and perform to their potential. Your success will rise with the motivation that everyone else is performing at their best. Obviously you have nothing to lose, always picture others working as hard as they can, and you will see your productivity level rise. You will enjoy yourself more too!
Some of the best leaders that I have known expect greatness from their coworkers. Having that positive attitude and hope of quality in a team has motivated others in the group. Trust escalates when everyone has the expectation that all members will bring greatness to the project.
Why not expect greatness from yourself? What do you have to lose? From there, bounce out to expecting greatness from everyone you work with, and against. You will work harder, and you will see better results.
So get out there and go to work, I expect greatness from you. Go and prove me right!