Games are entertainment products, not tools. It's acceptable for a game UI to draw attention to itself for artistic effect, but I don't want to have to put up with this when I'm trying to get work done. Instant state transitions become imperceptible as you learn how they work. An instant UI effectively functions as part of your body, just like hand tools do. Animations make this impossible.

Compare an ordinary pencil (no animations, movement is directly tied to your hand) to a pencil with a pompom on a spring attached to the end. Which is most fun for brief use? Which would you rather write a whole page of text with?

Maybe you dislike them, but that does not make for a fact.

Instant transitions are something I strongly prefer and use in practice. There's no question, I don't want my operating system slowing itself down to a factor (literally) of 1000x, pointlessly fading and jiggling and sliding and bouncing and wiggling. And, as this article points out, animations in operating systems often make a visually illegible mess in the meanwhile.

Animations might be a good idea in theory, but it doesn't seem like anyone has figured out how to do them right.

No they are not used everywhere. Some games with good UI use animations everywhere that an animation is appropriate. But plenty of good UI exist without animations. The point above is that no animation is better than an inappropriate animation.

You will also see plenty of cases where a screenshot captures incoherent frames.

Squash and stretch is a whole art style that relies on unrealistic frames.

Games are games, work is work. I disabled every animated transitions in my desktop UI. Elements appear instantly at full size in the place they rest and disappear instantly.

Reasons:

1) I'm doing that thousands of times per week, I know what's going to happen

2) It's my desktop, there is no one else who might be puzzled by a non standard behavior

3) It's faster.

By the way, it is a GNOME desktop on Debian 13.

Oops, I lied. I was about to click on Reply and I realized that the bottom panel (which on a standard GNOME is at the top) is on autohide with a short transition. Maybe because it's the only transition that I activate with the mouse pointer: I hit the bottom of the screen and while it's traveling the last pixels the bar starts sliding in. It's very fast.

Games are for fun. Wasting time in a game is fine, that's what it is for. (edit: not saying that pejoratively)

Other applications are to do things. They should do the thing and get out of the way as fast as possible. Animation-induced delays are fundamentally contradictory with that; they waste the user's time instead of doing the thing.