Good topic
And some interesting responses. This is something I've had to ponder a bit myself over the past few years. Bottom line answer for me is my 2 young kids, ages 2 and 5. They rely on me, and I on them. I can't bear the thought of not being able to see them growing and learning and all the fun that goes with that.
This has come into more clear focus relatively recently. Tree care is not my full time gig anymore but I do quite a bit on a part time basis. I don't do a lot of huge, nasty jobs anymore, I'm very content to let other people bid them. However, even the smaller, easier jobs can go badly wrong really fast and I have to tell myself to slow down or take a second look at something fairly often.
What really has brought it into focus is my hobby, whitewater kayaking. I love steep creeking, there's nothing in the world like it. However, I've lost 2 close friends in the past 5 years, both running class 5 creeks. As a result, I paddle very little class 5 these days. This past spring, I got vertically pinned at the base of a small waterfall and had to get roped out by my paddling buddies. The pin was marginally stable, I had plenty of air, but the water was very cold and I knew that I wasn't going to be able to stay strong for too long between the cold water and the effort I was using to stay upright. Problem was, my friends didn't know I was in trouble. We had skipped basic safety rules on an "easy" drop. I could see them at times and could see the clear pocket of water that I needed to get to if I was going to survive. I was very aware that they didn't know that I was in trouble, that I had a limited amount of time to wait for them to figure it out, and that if they didn't figure it out in time I was going to have to try to extricate myself, before I got too weak. I was also very aware that not surviving was not an option because of my kids. We estimated that I was pinned for between 5 and 7 minutes before they figured out that I needed help. Once they did, they rigged a stabilization line, then a pulley, and got me out within 1 minute. At the time, I sort of shook it off as a dumb mistake and a good rescue. However, I still haven't quite come to grips with the reality of what was going on.
There are parallels between paddling and tree work. Whether it's peeling out of the last chance eddy at the top of a big drop or making the back cut on a big top, you pass a point of no return. At that very moment, you become 100% committed to finishing. The crystal clear focus at that moment is very zen like to me. I find peace there. It is easier to be zen about it when you know that you have the skills to instinctively correct whatever minor mistakes are about to occur, because you're certainly not going to have time to think about it. To do these things successfully time and again, you have to be able to do exactly what Timber said, identify, eliminate, and minimize your hazards. You also need to know when to walk away. And when it's something that feeds your soul, knowing when to walk away can get blurry.
Kind of over the top, I know, but it's my .02 anyway.