Everyone who's ever worked in a modern office has experienced the pain. You sip your coffee, read your emails, finally settle in and start being productive when that coworker rolls up to your desk. You know, the one who either can't tell or doesn't care that you're in the middle of something (and if you don't know who that person is, well, then it's probably you). Thanks to the miracle of modern technology, a new Chrome browser extension has your back.