Never assume the other person has even basic information
On the way home, he asked some of the strangest questions. First, he asked if his little brother could come. Of course he's coming, I responded! He lives with us. I then wondered why he asked, did he think that kids just get arbitrarily left out of half of all the things their families do?
Then when we got to the house, he asked if he could come in! Of course, I responded! It's our house, your house! Then I wondered, what did I do to make him feel not welcome?
So we're inside and I'm recounting all these strange questions to my mother-in-law, wondering what in the world I've done wrong as a parent, when Jacob spots the cooler full of sodas and beer and says "The party is here??"
You see, it had never occurred to me to tell him that the party I was taking him to was at our house. So here I am wondering about all these deep things like kids growing up with two homes, four parents, parenting styles, etc and the whole problem was a very basic lack of information!
So next time you're talking to someone and you're thinking "they just don't get it!", maybe it's time to stop and go over the basics. They just might not have that really basic and really vital piece of information that you are assuming.