I've worked many soul-sucking jobs. You could hear part of your soul dying every time the doors opened into the recycled air-filled building. For most of my job career I talked to the elderly about their insurance. It could be very depressing and could wear on you depending on the calls you took. I was always considered, and knew I was, the more negative of the people I worked with. Mainly I was negative because of the system. I wanted to help these people but knew I couldn't and could do nothing to change it.
My job these days is more upbeat. I actually get to help people and it's one of the few jobs I actually like. I am no longer the "negative one." That role has fallen to about 30% of my coworkers and that crap is more grating on you than hearing about how someone is going to die if they can't get Medicare to pay for something. They complain about the kids, the teachers, the parents, the lack of God and basically everything else. I'd actually complain if I knew something would be done but I know nothing will be.