Earlier quoted context omitted.
> My fan comment was a joke about Slack's efficiency. It's less of a joke and probably just a statement. Seriously: even something as small as someone adding an animated emoji makes slack eat CPU :-/
I used to wonder why my ThinkPad sometimes ran for 12 hours and sometimes 5. Turns out that Google Docs has an animated cursor that doesn't just blink, it fades in and out using javascript. Animation cost several W on average. UX guys love animations because I dunno they are just psychos.
Brian Kernighan's COS333 page links to a goodui.org that recommends animations (in moderation) but also a bunch of horrible stuff.
So there's that.