There are some kind of apps that you always run in full screen, one of these would be apps that deal with your photos or videos. It’s just nicer to see them on the big screen, especially with the new and interactive photo stream in the latest iteration of the macOS Photos.app (It’s even running in full screen on their marketing material).

One of the many rough corners is still the “People” section of the app that allows you to tag people in pictures. I’m always baffled how this can be the main interface for tagging people. Can you see that tiny “Done” button up there in the menu bar? This could be so much nicer and fun to use.