When we speak today about a professional football player it doesn’t mean that he is doing it for a living, but that he is performing outstandingly.
A special feature of a pro is that he/she can direct things into a good direction even when his/her sentiments would lead him/her elsewhere. This is the specific mixture of self discipline and internal force.
Amateurs hope. Pros work.
You must consequently be better than others. That’s the characterstic of a pro. It has nothing to do with the fact that you are paid for your services.
If I have eight hours for cutting wood, I spend six sharpening my axe.