Looking back over the years, what was a constant source of frustration with all user interfaces I've ever used? Speaking in general, it's the assumptions they make about me that just aren't true. But that's too general. I have a more specific complaint in mind now.

You're on the phone, searching for stuff, tapping the links in the browser and apps. There's a link that looks promising, you move you thumb towards it, and decide to give it a tap.

But lo! - 0.1 seconds before your thumb hits the screen, a UI element pops underneath, asking for confirmation or whatever. There's no time to read what that thing wants. There's no time to change the decision. You just give it a tap and it's gone. Maybe it asked you to confirm a download. Maybe it was a survey asking a yes/no answer. Maybe it was the OS asking for confirmation before it performs a factory reset (just kidding, but not entirely impossible).

Why are you doing this, UI? Why do you imagine my reaction time is superhuman? How can I possibly process that information, and respond, within the time it takes a bullet to cross the street?

Things get even worse when the system is overloaded, sluggish, things take time to respond, and then pop on the screen when you least expect them.

All UIs should implement a brief delay before they accept feedback from the user. I don't know what the best value is, but it must be some fraction of a second. Buttons on pop-ups should ignore taps during that time.

This should not be a per-app decision. The whole UI must implement this delay.

Some apps (such as games) may request exceptions, but those should be granted only sparingly and wisely.

I think this change would produce user interfaces that are far less annoying.