I first encountered the paradox of relaxation in years of martial arts training:
The more relaxed you are, the faster you will be
If I come to a kung-fu class tensed, I would inevitably get my ass kicked @#$$!
However, if I am relaxed, I am able to have a higher reaction time, discern attacks and be able counter-attack with speed.
This is counter-intuitive. Instinctively, our muscles and body tense when face to danger. Why should we learn to be relaxed instead?