This should be a basic requirement for all games. Even before I was married my mom would call or someone would ring the doorbell. And when I was a kid I had to go down to dinner or take out the trash.
These days of MMOs and other coordinated time-sinks make me miss the simplicity of pausable single-player and turn-based multiplayer sometimes.
Hell, even the single player games are getting to be unpausable. How many cut scenes are there in GTAV? And if other duties are at hand, the only option is to skip the story line so you can pause.
These days I can at least hit the Home button on a Wii U game and expect it to work. Emulators are still hogging save-states all to themselves, though.