Someone coming unexpectedly out of nowhere? You have no sense of logic, do you? Not just accidents, someone could have serious things on their mind, be really tired or seriously stressed out. All of which could lead to a moments lapse of concentration and you've dropped something.
Don't tell me you've never dropped anything in your life. If you're not able to accept the fact that no matter how careful & vigilant you are, accidents can and will happen. Just because you've never dropped your phone, doesn't mean anyone that has is stupid or a monkey as you say.
By the way, I never said I've dropped my phone. I can just understand that things happen. But if you can't understand that, it says more about you than someone who might drop their phone.