yes, Life is very strict teacher! and sometime or often - actually also cruel.
sometimes it may feel like - it is too hard to continue live it.
also there is a saying: "nobody gets out of Life alive..."
but some people express opinion that to continue living - may be even more difficult.
and yet - must do that! no matter what ...
because that's the meaning of Life: to Live!
and to pass all the exams which Life prepared for us.