I have a 2yo ds and a 4.5yo dd. We have sharing issues. I mostly don't allow them to have things that are exclusively theirs -- most toys are shared no matter whose they are. Dd tends to freak out (and scream loudly ) if ds gets something that she says is "too special". It is not always consistent which items are too special, and she just leaves them lying around, so there's no chance that ds isn't going to get them sometimes. I have talked to her about keeping special things in her room and closing the door, but she rarely does it.
I often feel like she's just doing that thing of seeing someone else with a toy and thinking "oh, I want to play with that". I think that too, but I don't snatch it out of the other person's hand. Am I expecting too much for her to share everything she leaves lying about? Should I help her to keep some things sacred? At this point I only take things away from ds if the item or the child is in imminent danger.
Sorry for the ramble. I'd love to hear your ideas and experiences regarding sharing, etc.