Better to underestimate and over-deliver than promise something you can't do

I almost had this post done, when I decided to delete what I wrote and start over, because it sounded like I was being way too critical of:

1) people who promise to meet you at a certain time and are late, even after promising they'd be there "soon," which sometimes could mean a half hour to a full hour
2) workers who promise to show up within a window of time, then show up after the window has closed, after not even bothering to call, and you have to call the company to find out what's going on, while they apathetically promise that they'll be there "soon"
3) tradesmen who promise they'll show up early, i.e., "you're the first in line, then you can get out of here when we're done," then don't show up until about two hours later, with no explanation or phone call, not even bothering to answer phone calls or emails to verify that they're even coming
4) companies that promise services that will arrive in "less than half an hour" and keep promising mere minutes but show up in three hours
5) shipping companies that promise to deliver a package by a certain day, then lie about not being able to deliver said package, even though there's always someone there to receive it
6) people who say they'll call back "right away," and the call never comes, or comes some days later

I could go on and on and bore people with details of people and companies that promise on-time something, and rarely live up to what they say. It would be much easier and more polite and honest to simply say what they really mean. If people aren't able to be somewhere, promising the impossible doesn't make us feel better; it makes us feel duped and annoyed if we're tight for time. The next time someone promises me something, I'm going to ask them what they really mean. Are they really going to be there in a few minutes, or are they going to be quite late? Are they really going to show up by 2:00, or are they not going to be able to make it because they have a lot of things lined up before me?

The other day, I figured traffic would be bad, so I told someone I might be 15 minutes late. Instead, I was 5 minutes late. I told someone else I'd get something done by the morning. Instead, I got it done that night. It's a lesson I learned from Scotty: better to surprise people by getting something done faster than they expected.