Learning the Unspoken Rules

Do you have trouble communicating the unspoken rules of life to your child?

Both of my children like to "pick our seats" when we eat at places like Chipotle and Panera.  Places where I can order and watch them at the same time.  Oldest almost always picks the seat closest to where other people are sitting.  Sunday afternoon, for example, Chipotle was empty but for one side table of 3 teenage boys.  Where did Oldest pick?  The side table right next to the teenage boys, of course. 

Then when I said, "Oldest, pick somewhere different," I was met with "Why?  This is my favorite table!"

All did not end in a tantrum, as it would have 3-4 years ago, and I am very thankful for that! 

But when we sat down and I tried to explain the empty room and how it just wasn't right to sit right next to other people, I was met with a blank stare and this response:  "Yeah, but, why wouldn't I want to sit next to them?  I can talk to them or listen to them if we're closer." 

Well, yeah. 

I had to tell her that this was one of life's Great Unspoken Rules - you just have to do it even if doesn't make sense.  She didn't get it.

What about you?  What unspoken rules have you had to teach your children?  How did you do it?  Any funny stories to go along with it?