There's a hidden Power in Pleasure And Pain that we all overlook. When you realize that "chasing pleasure or running from pain" is a trap, because they are really One and the same thing. Instead of separating them as to make a distinction between them, you can now more consciously have the experience of the actual simple "Sensation" of what is actually experienced, to become more clearer of the action that needs to take place in order to have a more sensible and favorable outcome or even physical manifestation.
In other words, without making a distinction between pleasure & pain, one can move and work the body in such a way that it actually helps to strengthen it and effectively unlock its developmental processes, instead of forcing the body through the old "no pain no gain" adage, punishing it through destructive means that often impede the body's intelligence to function more efficiently in its regenerative processes.
Let's look at the extremes of Pleasure and Pain. Too much leisure (Pleasure) and the body, intellect, emotional, and energetic processes become weak and listless. Too much stress (Pain) and the body, intellect, emotional, and energetic processes begin to break down and quite possibly move pass the point of recovery - which is not the most intelligent way to move or work.
By "playfully" engaging the body in our day-to-day activities, this allows for more energy as well as oxygen and nutrient-rich blood to flow through the body, which is very beneficial in its regenerative and rejuvenating processes even at the cellular level. This helps the individual become and feel more "responsible" for the way he/she develops themselves because there is no true freedom or power without full personal individual responsibility.
On the other hand by being more "serious" that's actually more irresponsible in your day to day activities because you will tend to stress and overwork the body which also depletes it of its vital energies and make it more difficult to regenerate them. When your energies are low, this makes it very difficult for you to take clear and precise action. Unfortunately this is what happens when you take yourself and life too seriously.
If you experiment right now, you can actually feel your energies drop if you take a more serious attitude about anything in your life. Be it work, meeting with friends, intimate relationships, going on a vacation, or whatever you hold dear.
Ironically if you work on yourself to become more "playful" in life, you'll actually become more responsible. In other words your responses become more "sensible" in your thoughts, words, energy, and actions, Instead of "chasing pleasure or running from pain", you'll feel more in your power to take clear action and create more favorable outcomes and actual physical manifestations that you see yourself enjoying in real life.
If you can see them and use them as being ONE and the same THING, this is the hidden power of Pleasure & Pain: Responsibility. Power. Freedom.