Teaching a young child to share, as in 'requiring' or 'guilt-tripping' him or her to share, usually interferes with their willingness to share. Here are three things to think about:

1 - Young children are keen observers of adult behavior, and in the adult world, they likely, by even age 3, have perceived that adults are not as willing to share their own personally valuable and meaningful items with strangers or even acquaintances as they are in being sure they (their own children) do.

2 -  They are in the middle or at the end of learning what ...

My own adult children now know that insisting that children say "please" and "thank you" will likely result in their saying that (especially in our presence), but whether others feel the gratefulness or feel the appreciation depends. Is it from the heart? Or because they "should," a part of "being nice."  "Be nice!" is what many of us were told by our parents. While there is certainly nothing wrong with being nice, it can ...