Mine! Mine! Mine!

Sharing.   Why is it such a difficult concept to learn?  Why is it such a difficult concept to teach?  Why can't we all just get along!?

My house frequently sounds like that flock of birds from the movie Finding Nemo: "Mine! Mine! Mine! Mine!"

I've been a parent for 22 years, so one would think I would have figured this one out.  One would be wrong.

Nothing makes me more insane than dialogue like this:

"Mo----Om!   He won't let me play with his toy car!"

"It's mine!  I don't wan't her playing with it!"

It makes not one bit of difference that the owner of the toy car (or WHATEVER! the object of the moment is) is not only not presently playing with the coveted toy, but in all likelihood hasn't played with said toy in days or even weeks.

However, the fact remains, he owns it.  It is his.  He does NOT want his sibling to play with it.

I always try to intervene with a bit of mom guilt:

"Come on, sweetheart, is it really that big of a deal if your sister plays with your car?  You weren't playing with it.  How is it going to hurt you if she plays very carefully with it for a while, and then puts it away....?  It would make me so happy if you would share."

"No!   She never lets me play with her stuff, so she can't play with mine!"

Well, that got me no where.
How do you reason with that bit of logic?   Am I supposed to FORCE him to let his sister play with his toy?  Is that really sharing if I intercede with force?

I have absolutely no idea......any suggestions?

Enjoy!
~Lisa