Recently I saw 2 children who both wanted to play with the same toy at the same time. One child was trying desperately to wrestle the toy away from the other, while shouting, "Share! SHARE!"
To the child urging "SHARE!", sharing meant "you should give me what I want." Sharing was seen as something you ought to do for me, not something that is voluntary.
It reminded me of the metamorphosis in my stance on forcing children to share.
I started out my parenting journey over 17 years ago following the popular idea that since sharing is good, we should strongly encourage and even force children to share with others. I mean, if it's a good thing to do, then our children should do it, right? And if our children don't especially want to, well then, we just have to make them, right?
Like writing thank you notes and taking antibiotics.
Then I started noticing that forcing children to share only made them hand over the object grudgingly, but when they came up with the idea of sharing a toy on their own, they seemed to take joy in the act.
It was about that time that I read about this very idea in one of the many parenting books I owned. The idea is that as humans, sharing can give us great joy if it is voluntary. Forced sharing, however, can cause bitterness and squirreling away secret stores of goods that we don't want others to know we have.
I don't exactly pay my taxes with glee. I hand it over because it is the law. I grumble over what I think is irresponsible usage of my payment. I disagree with the programs funded. I resent giving my hard earned money to folks who did not earn it.
What is the difference? One is forced upon me. The other is voluntary.
I no longer force my children to share their toys or candy. We regularly talk and read about how Christians ought to be kind and generous, and I praise them whenever I see that they do those things.
Occasionally they receive a toy that is intended to be a group gift for everyone to use, like our Wii  or a swing set or doll house. In that case, sharing is mandatory.
But if they get a new toy or someone gives them candy, I allow them to enjoy it without imposing any guilt about how long they play with it or whether anyone else got any. We have talked often enough about boasting that they know it would be rude to gloat, so that would be extinguished, but I do not force them to share.
More often than not they see that playing is more fun when it is done with others, and they voluntarily offer to share the toy. The joy they get in coming to that conclusion themselves can not be matched with forced sharing.
Forced sharing creates bitterness. Voluntary sharing creates joy.