Thinking vs. Doing

Why is it often more effective to just clean a drawer than spend time psyching yourself up to do a deep clean of your whole room?

There is something about involving our bodies that creates evidence, belief, and motivation at a stronger or deeper level. 

I can think positively about my ability to clean my room for awhile.  But thinking less and just getting up and cleaning one small thing seems to work better. 

My mind is powerful, but combining it with the actions of my body is even more powerful.