I regret ever using X/Emacs for 5 years with two reasons.

The biggest reason is, I have arthritis on my left pinky thanks to Emacs. Now I need to use an expensive ergo keyboards (thumb for ctrls)

The second reason being, vi is what I am forced to use for many linux default editors. I never learned it, and always look up google for commands.

(optionally, extending Emacs is pain as I never understood the point of lisp).