Late Is The New On Time

I'm beginning to realise that meeting times are just very loose estimates. When people say meet me at such and such a time, they really mean plus or minus about 20-25 minutes. Which is not that bad considering, but I could be doing other things in that time. I try to be as punctual as possible for the most part. I get to work on time, and get to my meetings on time. I leave early enough to be early. If I'm late then I'll call.

What really gets me is when people assign a time and then show up late themselves.But now the new thing is that people call and say they'll be late at the time they said to meet. What's that about?