Learnt BASIC on a C64.
Spent several years writing DOS programs in Turbo Pascal. (Oh how I miss having to optimise my code.)
Fell in love with OS/2 the first time I read about it. Tried it and never looked back.
Been using Linux for some 2.5 decades now, still coding daily (different languages, mind you), but there's never been a desktop like OS/2's Workplace Shell. There's just no going back to application centric GUIs.