Remember the scene in Finding Nemo where the seagulls close in on the fish while squawking “mine” “mine” “mine”?
They obviously wrote that scene after witnessing a toddler’s playdate.

In the early toddler stages, learning to share with the people they know and love, is a huge feat. Convincing young toddlers to share with other kidlets at the playground, is rarely going to be a success if they haven’t yet gotten the hang of sharing with family members. At their age, they don’t trust other wee “strangers” that easily.