Mostly curiosity. I've had two potentially life-threatening mental health issues at different points of my life, an eating disorder when I was very young (it did not get very severe though) and a substance addiction much later (which was severe and could definitely have killed me). I did not use any professional help to beat the eating disorder and tried therapy, for the first time, in a period when I was actually doing very well (it got worse later for a while. I got curious about therapy and what it could potentially achieve while engaging in an addiction recovery community, where many people talked about their experiences with it and there were some therapist or ex-therapist members. I definitely did not expect it to save my life, it was more a very open "what will happen" kind of thing. Some of the curiosity was also coming from my profession in mental health research, where I encountered and worked with many Ts and psychiatrists. It definitely did not achieve anything even close to life saving, actually had a very nasty substance relapse while being in therapy and, I think, my first T's approach could have made it worse if I let it.

I don't know if I could ever name one thing that I would consider life or death regarding any phase of my mental health, typically just one thing does not have very significant effects on me and better to use a bunch of things to achieve change.