Taking your own life is seen as a mortal sin by most Christian traditions, mortal sin as in there is no forgiveness for this and you go straight to Hell. Not sure about other traditions but in the case of Orthodox and Catholic Church you are, for example, forbidden to be buried in sacred ground if you take your own life.

If you are curious you should read a bit about the history of Christianity, e.g. a Eastern Orthodox Christianity tends to be more entrenched in tradition than modern Catholic Christianity. You don't have to be a believer to read about history.