Once there was a water jar that had a long hairline crack in it. The Jar leaked so badly that, when it was filled to the brim with water and carried back to the house, by the time it got there half the water had leaked out. Nevertheless, the servant of the house used it daily, along with another jar that didn't leak one bit. After several months of constant daily use, the cracked water jar was very depressed at the fact that it had only been able to get half as much water to the house as the other jar. When the servant heard the jar moaning about this, he said, "You have nothing to be ashamed of! You did the best job that you could. And, look – I always carried you on the right side walking back to the house, and the other jar on the left. See the path??? On the right side, there are beautiful flowers all along the path, but on the left, nothing is growing - it has been too dry this summer."
So...when we grow discouraged about not being "productive", remember, the cracked water jar, which was doing a job it didn't even know it was doing at all...that the whole water jar couldn't have done.