The Hidden Meaning of Just Do It. In particular, this part:

The trick is in the meaning of the word "just". When somebody says "just do it", they are trying to communicate that you should not do anything else. It might better be phrased as, "Only do it, without thinking about anything, not even about what you're doing. In fact, don't even do it, just watch yourself doing it, but don't actually try to do anything."