I jotted this down a number of years ago and it has never left my thoughts:
"We each do the best we can. My best may not be as good as your best, but it's my best. The fact is that we know when we are doing our best and when we are not. If we are not doing our best, it leaves us with a gnawing hunger and frustration. But when we do our level best, we experience a peace."
-Sister Marjorie Hinckley