this is a standard definiton of time used today that bears no real conviction whatsoever, fifteen minutes can be anyware between five minutes and five hours or possibly longer if the individual stating the fifteen minute deadline is a real flake. This is a timeframe typically given by an individual with a minimum 30 minute drive to thier destination that hasnt even woken up yet who is already late when you call them to find out where they are. This timeframe is also given by the same individual when they are stuck in traffic a minimum of 15 miles away that is moving at 5 miles an hour, we can all do the math on that one.
Me: Dude what the fuck, ive been waiting for you for like an hour where the hell are you
Friend: Ill be there in fifteen minutes