I have two chores at my house.
The first is recycling.  I was told it was my job because I'm "earthy" and I am good at organizing.
Truth be told, I do enjoy recycling, I feel like I'm doing my part and have even created a system for organizing paper, plastic, glass and aluminum.

The second is vacuuming.  I'm pretty sure I was just given this job because no one else wanted to do it.  Unlike recycling, which happens every week, I often wait large amount of time in-between each time I vacuum.  I just don't think the carpet looks dirty, so I don't do it.

When I do vacuum, I enjoy it when I get to vacuum up an actual mess.  A spill on the rug.  Beneath the couch that hasn't been moved for months.  Recently, around a real Christmas tree.
It makes me feel like I've accomplished something.  I can see the mess disappearing.  I can see the result.

Sure I know that when I'm vacuuming up the less messy spots I'm still cleaning little microscopic dirt, hair, and other gross stuff that needs to be cleaned.  But it's not as fun.  It's not as enjoyable.  It's just not the same.

A lot of the times we don't see the result and it is not the same as seeing the result.  We can easily become unmotivated and lazy by the lack of result.  Of course when we see results we want to keep going, keep looking for more mess, keep cleaning.  We are motivated by what we see.
But we don't always see the results.  And I don't think we are meant to.

If we were able to see the result, the why, the reason we do it changes pretty quietly.  It's not about what is behind the action so much, as what you can get from the action.  
It's not meant to be about he result but about the heart behind it.  It's meant to be about the why, not the action itself. 

If we always saw results of every good work we did, it would too quickly increases our motivation from glorifying God to glorifying ourselves.  I think God keeps us from seeing the result to help us, to bring us closer, to help keep our hearts a glorifying position.

If I only vacuumed the big messes, the one I could see with my eyes, I would miss a lot of dirt that I can't see.  I would miss out on a lot and it would be just because I couldn't see the result.