I am definitely considered mentally ill as I have several diagnoses and hate life despite having had good circumstances at times of my life. No matter where I go, I am miserable and absolutely crumble and suffer over the mildest inconveniences. I have tried almost all treatments to no avail even though I think suicide is more ideal and realistic.
On top of the mentally ill aspect, I would like to say that certain combinations and types of events/experiences in life can permanently change someone to where they are too aware of atrocities and the horrible nature of things to be able to cope. For example, being a happy person who has never experienced horror seems to make someone more inclined to not think twice if they see someone suffering through something awful (homelessness, drug addiction, abuse, depression, etc). Many people will just perceive these things as bad, where as I see them and see that they surpass simply being bad.
These sufferings are absolutely horrid in their existence and are not moderate in their detriment to the people who endure them. It just gets harder to live when you understand exactly what true suffering really entails and that there is an excess of it in some form in most places. One may argue that mental illness makes you fixate on these things in an unhealthy way and don't get me wrong, I do not think it's helpful to fixate on tragedy and suffering, but it is a very grave occurrence in this world and is hard to not feel on a visceral level when you know the feeling.