Kids today will never believe this, but it used to be an important user interface design consideration that buttons for controlling stuff (like a media player, or paging through a series of photos) not cover up the stuff that the buttons control.

Imagine: videos, where the play and pause buttons were not on covering up the playing video content for any amount of time. “See next photo” buttons that didn’t overlap any part of the current photo you are looking at.

We can have it all again some day, I believe.