Taking one's own life.
Suicide is the strongest possible protest against, or perhaps the only escape from, an intolerable situation.
There is but one truly serious philosophical problem, and that is suicide. Judging whether life is or is not worth living amounts to answering the fundamental question of philosophy. All the rest - whether the world has three dimensions, whether the mind has nine categories or twelve categories - come afterward. These are games; one must first answer the fundamental question of the reason for living.
Suicide only rejects the situation, without offering alternatives. Examples of suicide tend to reinforce the incorrect idea that this is a viable way out of or a solution to problems. Every suicide or attempted suicide bears the burden of being an evil example.