Hobbies always change when they become a job because it transitions from well thought out, interesting and creative projects to mass production and monotony.
As a hobbyist you have the ability to discover and work on unique, novel projects, without stress but professionalism is about consistency and speed.
Usually by running the business you can dedicate some time and resources to the fun and novel stuff. Thats how I run mine at least, as a woodworker. I don't crank out high grossing trendy stuff day and night but take the time to explore new ideas and get creative with it. That and using handtools instead of power tools.
I mean, I 100% agree with this one. If I'm going to be at work eight hours a day, five days a week, I better damn well enjoy it.
I'm a software dev, too, but have always left companies / teams soon after a Lumbergh took over. That was always a very good career move for me, and I am almost always pretty excited to go to work.
Plus, Lumberghs will be there for things you don't enjoy as well. That would just make it harder, at least for me.
I'd say the tasks and role of your job should at least be enjoyable enough to not hate it but what I think is even more important (and makes me enjoy my job) is the work climate, being appreciated by colleagues / customers / management, and a sense of purpose.