Credit: Google Images
We are all going through this life alone with no path or supposed plan. It's like being lost in a forest without any foreseeable solution. 

Sometimes, all we really need for a day to turn completely around, is some kind reinforcement that what we are doing with our time is actually worth it. That we matter, what we are doing matters. 

A simple "thank you" or a "good job" goes such a long way in your subconscious feeling that what we are doing is right, that our path is good.