... I help so many users that run one program full screen. I just sit back and shake my head as they constantly switch from one program to another instead of arranging the program windows to see everything they need at one time.
Power user for multiple decades here. I have a big monitor and I run all my apps fullscreen. I have for the last 15 years at least. I do this because whatever I'm looking at - code, shell output, web pages - I want to see as much of it on the screen as possible. Running things fullscreen also means window-management buttons, when I need them, are located at screen corners where they're easy to hit.
When I need to switch apps, I just alt-tab. It's super fast. If an efficient workflow that's different from yours pisses you off, I feel sorry for you.