I think I'm going to blame mobile phones for this one.
In the old days, you would make a plan, sometimes weeks or months in advance, and you would have the relevant details (when, where, for how long, etc) way beforehand and set in stone. This was because you didn't have a mobile that you could use to text someone two minutes before you were supposed to meet them, telling them you all of a sudden weren't coming.
Mobiles have enabled us to call our parents for a ride or our mates for a spur of the moment ice cream mission, but they have also encouraged us to be poorly planned and inconsiderate of other people and prior plans.
Here's an idea, youth of today: make a plan, stick to it. Want to go to dinner? Let's decide to go to dinner! And let's actually go to dinner, when and where we said we would.