If you're not absolutely sure they want your feedback it's best not to offer it.
When the data and their model don't match, most people discard the data.
We structure our world so we will not receive feedback that threatens our view.
We don't even wait to ignore feedback, but actively take steps to prevent such feedback from ever happening in the first place.
We tend to learn only in new situations. In new contexts.
The more we try to control, the less influence we are likely to have.
Don't concentrate on giving feedback; concentrate on being congruent - responding to the other person, to yourself, and to the here-and-now situation.
The less investment you have in changing the other person, the greater the likelihood that each of you may grow.
Improving a relationship doesn't always mean making it closer.