It is the quietest and meekest people who are often capable of the most sudden and unexpected violences for the reason that when their control does snap, it goes entirely. (Hercule Poirot)
In anything that does cover the whole of your life - in your philosophy and your religion - you must have mirth. If you do not have mirth you will certainly have madness.
We feel that our actions are voluntary when they follow a decision and involuntary when they happen without decision. But if a decision itself were voluntary every decision would have to be preceded by a decision to decide - An infinite regression which fortunately does not occur. Oddly enough, if we had to decide to decide, we would not be free to decide