We are a social species. 

And we form social bonds through sharing. 

Sharing our thoughts, sharing experiences, sharing conversation, sharing a meal, sharing a vision.

We are constantly finding things that we can share with others we consider our tribe.

Sharing is our default.

When you are faced with an intuition to not share, it is likely because the one you are considering not sharing with is someone you do not think is a part of your tribe or family (in the context of what you're considering not sharing).

What we're willing to share or not share with someone tells a lot about how we feel about them.