The whole "integrated development" experience. Take it or leave it, but old farts like me go all the way back to poring over code on printouts since your only window into it was one file at a time in an 80x25 terminal - not terminal window, actual terminal or, by then, terminal emulator.

That does affect later habits like, for example, hating the information overload from syntax highlighting. And don't even get me started on auto-indent.

Whereas younger colleagues, whose habits were formed in the era of much more sophisticated tools, have dozens of files open in tabs and can follow, say, a "where is this defined" or "where is this driven" (this is RTL code, not normal software) in an instant. Keep in mind some oldtimers had really fancy emacs setups that could do that, and vi users had things like ctags.

They imagine that they're being more efficient.