"I hope to get a B in this class" or "It has to be at least five pages" or "I want to run 3:10:59 and qualify for Boston" or "we have to run eight miles today" or some other statement of work. Now those are all very good goals. There are a lot of people that would love to get a B in that class. Billions of people will never qualify for the Boston Marathon. However, I think you are better.
This may not apply to everyone that reads this blog but since I know most of you here it goes: If you do something, do it. None of this wishy washy half effort stuff. Get the work done. Set a higher standard for yourself.
I have found that whatever standard I create for myself I usually end up achieving, but just barely. Examples: I just wanted to pass a class (twice), I got a C. I wanted to break 33 minutes in the 10k and I did by 1.5 seconds. I wanted to get above 7000 meters this summer and I got to 7030 meters.
I don't always hit my goals, in fact I fail a lot. However, setting these goals changes my attitude and focus so that I put in the work necessary to achieve those goals. Many of my failures are also failures by the slimmest of margins, which in retrospect are sometimes as good as the goals. Setting a higher goals makes you figure out how to get there. Instead of thinking of tasks as impossible you can understand the steps necessary to get to that level.
I also think we are limited by our goals. As soon as we set the bar for ourselves we want to just barely get over that bar. Anything much higher or harder is seen as nearly impossible. By setting higher goals we also change our thinking so that we fail at a higher level. There are many examples of this: the kid who gets the highest score in the class on a test and still asks the teacher why she got two questions wrong or the guy who PRs by 30 seconds in the 5k and is disappointed that he wasn't 15 seconds faster. I've seen these people and it's not that they are better it's that they hold themselves to a higher standard.
"Shoot for the moon. Even if you miss it you will land among the stars." — Les Brown