I just got a phone call from an iphone which triggered several tabs of gmail in my web browsers, my phone, facetime, and i think somewhere else ringing. It basically killed my laptop, facetime crashed, and I couldn't answer the phone. WTF people.
This happens to me on a regular basis. Throw in bluetooth headphones into the mix (who knows which device they're currently connected to!) and I have basically zero idea what will happen if I manage to click on any one of the dozen things popping up in my face.