I think most of the time we can tell when a person is looking for affirmation and when they want help with a problem. If you want to know why your triangles all ended up crooked, it's frustrating to be told "Oh, it's just beautiful as it is!" and "Don't worry about it!"
And really, if someone has just finished 36 blocks, it's a little late to tell them that their background fabric doesn't have sufficient contrast to display the star points. It would just frustrate them.
There is always SOMETHING nice to say!