

A big plus one to ambiguous switches. Two things I didn’t see already mentioned:
First: if you have content that requires horizontal scrolling, like a big table or report, that horizontal scroll bar needs to be on the screen, not at the bottom of the report. I shouldn’t have to scroll hundreds of rows vertically in order to be able to scroll horizontally. While we’re at it, column headers need to stay on screen when you scroll vertically past them.
Second: if there are two choices, identifying which is active needs to be more than just changing the color. Outline that shit or add a halo, throb, or something. Sometimes a user depends on tabbing and not using a pointing device or touch screen, especially when using assistive technology. This is especially heinous when the content is consumed on a tv using a remote control, such as a streaming service or DVD menu.
I have this weird habit of buying the less popular but arguably better thing. I went with windows phone, a nook instead of a kindle, an zune mp3 player, and a Mustang MachE instead of a Model Y. That last choice might have been the only one that ultimately paid off.