...it's people who are late.
late people are telling you, in a sense, that your time is not important. at least, not as important as their time.

there are two kinds of late people:
a) the first are the people who do not understand the concept of how long it takes to do things. I have friends who will call me up and say, "okay, so i have to stop at Sobey's to pick up something, then i have to drop my kids at my inlaws and then get gas, so i'll be at your house in 5 minutes." um, five minutes? i know that it will take this person 5 minutes just to get the kids into the car, let alone get groceries and gas.

b) then there are the people who just live on their own clocks. if a party starts at 7, no problem, let's get there for 8:45. if a movie starts at 8, no biggie, we'll get there at 8:05, because the people (the on-time people) we are seeing the movie with will be there 40 minutes early to save us seats.