To me, Being a mechanic is not about turning a wrench, or installing a part. It's about problem solving, thinking things through and testing a persons patience.
With automobiles, I have always worked for myself, there just is not money in it to work for someone else, in my opinion it just is not worth the headace.
Now, I did diagnose and repair commercial lawn equipment, and commercail spray tanks, and fertilizer application equipment for a very large corporation, which is nothing near as complex as a car, but paid good, and the customer clientel was much more rewarding. I advanced to STORE MANAGER ,and I had that job untill they were purchased by a much larger coproration ,aka competitor, and then they fired me.