Trust issues

They likely don't trust you unless they appear that way to everyone. Many possible reasons. Someone may have great wealth, but don't want others to take advantage of them. They may be involved in something illegal or top secret. Some are natural introverts and have a limited need to socialize and feel safer keeping to themselves and avoiding crowds. If I suddenly came into great wealth, I would have reason to keep that a secret and only people at the bank would have any idea how much I had.

That's actually me and I am an introvert.

hiding the big bad wolf somewhere

It could be they prefer to be that way not everyone needs to advertise their life to others.

The might just value their privacy

....distanT...

They like their tiny world.

They may be an introvert.

It could mean they have trust issues, if they’re that way even with people to whom they [b]want[/b] to be close.

I would leave them alone, they become too unimportant for me too quickly.

Im that way