I know... not much. And it's the same kind of argument one would use when postponing say, garden work, cleaning the oven, etc. I have taken a vacation day next week to get this done - not just the macOS upgrade of course, but a long list of pending household tasks.
Especially since the update downloads in the background and doesn't require your input after starting it. You can start the update, go do something else, come back and hour later and it's done.
Ahaha yes, and then you're left "only" with a few hours figuring out what broke in your setup because stuff like /usr/local was "liberally" modified by the update. Plus, of course, oops all your 32bit games are ded.
(Yeah sure, not your average Mac user, but still - don't discount the pain that any arbitrary update can and will inflict).