The "why did it get slow" complaints happen when the animations aren't fast enough. The brain doesn't need a lot of time to register motion, but many times desi

The "why did it get slow" complaints happen when the animations aren't fast enough. The brain doesn't need a lot of time to register motion, but many times designers will use a slow and laborious animation to really emphasize something appearing. See Google's material design: it is based on the philosophy that interfaces should behave physically, and you'll see that it feels incredibly snappy. Check out these demos: https://material.io/design/motion/speed.html https://material.io/design/motion/speed.html Example: you can't effectively convey a menu becoming a button without an animation. Without an animation, the menu disappears and a button appears, but there's no reason to believe that they're related. A 100ms tween from one to the other is all you need. Our brains are very good at relating motion, not objects blinking in and out of existence.