Almost everyone, when asked, would say they are happy to be alive. Even those in extreme poverty, the severely disabled, and the mentally ill take great joy in being alive. 
This is reflected in the behaviour of many people. There are endless avenues for suicide all around us (tall buildings, noxious car fumes, rope) yet, comparatively speaking, very few people commit suicide. This is because almost everyone believes it is better to exist than not to exist.