Should there be limits to being authentic?

How much honesty is enough / needed? = how much authenticity is required for different relationships?

If we are told that being authentic is essential to building trust with others, then how much do we reveal of ourselves while being authentic in our relationships with them.

Here's an interesting Ted Talk on authenticity and leadership from psychopaths.

While the similarities to leadership are intriguing, the speaker raises critical points about how much authenticity is required for us in our relationships.