"At the heart of every suicide lies one and the same thought."
Namely: what happens in life is not what, in my opinion, ought to happen in it; consequently, life has no meaning and is not worth living.
For example, Romeo kills himself because he cannot possess Juliet. For him, the meaning of life lies in possessing this woman. But if the meaning of life truly consisted in that, how would it differ from absurdity?
Besides Romeo, forty thousand noblemen might have found the meaning of their lives in possessing the same Juliet, so that this supposed meaning of life would negate itself forty thousand times over. It turns out that the suicide was disillusioned and despaired not in the meaning of life but, on the contrary — in his hope for its meaninglessness.
He had hoped that life would consist solely in the satisfaction of his blind passions and arbitrary whims.
Vladimir Solovyov, The Justification of the Good, 1897