This is the way. Life gets so much easier when you live by honesty and surround yourself with others who also live by it.

Sometimes I cancel plans with a simple, "Hey, I had a long day and I'm pretty sapped for social energy right now. Could we do something tomorrow/on the weekend/next week instead?"

People who get it, get it. People who don't get it, aren't people I'd likely hang out with in the first place.