Here's the thing, though. Maybe I don't have a business meeting; maybe I'm supposed to go watch my kid's soccer game and I allotted literally an hour for a fifteen minute meeting, because I know this guy shows up late, and here he is an hour late. Am I supposed to tell the kids to just play soccer an hour early so I can watch the game? Should I miss the game just because this guy can't be bothered to get somewhere on time? Should I allot two hours for a fifteen minute meeting?

At what point does that become less reasonable than expecting other people to show up at the time they agreed to show up?