While in the military on active duty you're ordered to appear 15 minutes before any meetings, formations, etc. Reveille (wake up in the army) is at 5 a.m. sharp. So, what happens when you are on leave or out of the service? Medical experts say the human body operates on it's own internal clock. Most ex-military people and many others have an automatic alarm clock that goes off every single morning at 5 a.m. Good luck sleeping in. But, even with all of that no one is ever on time for anything anymore. Just making the train or flight to somewhere, showing up late for a concert, being hours late for most things is the norm these days.
It's just the way of things and we may as well accept it. So, don't expect friends or relatives to show up when they are supposed to for Christmas or for your birthday party, etc. Tell them, "oh, just come whenever you get around to it!" "We'll start without you!" It works both ways you know.