For example, when your YouTube app crashes/hangs on the Xbox One, returning to the menu does nothing as the app pauses/runs in the background. You can hit the menu button (akin to a right-click) on the YouTube icon and select Quit. If you run YouTube again, it'll still be running and crashed. The trick is to menu button and quit YouTube and then run a couple other video apps (usually Netflix and Hulu do the trick). This is usually enough to fully offload the YouTube process and allow it to run again.
This is how Microsoft's flagship entertainment console works. In 2016. Seriously.
Everytime our cat sitter watches our place, I have the Xbox 360 hooked up for her to watch videos on. It's easier to use and more reliable.