You'd be, if you got into computers only recently. It got this bad.

Only those who have used systems yielding low input latency (e.g. Commodore 64, BeOS or the Amiga) can tell that something is very wrong.

Sanity.

Whether sanity and productivity are correlated, I won't go into.

When you've experienced low latency, high latency is very noticeable, and drains mental health.

Yes, that's the most probable. I use a M3 Max so nothing is really slow but speed difference between vscode and Sublime is abysmal.