Yes we do have to do that.
And i think is one of the good reasons to be there. To bring out quality from their creative mind.
That doesn't mean that you need to give opinion 24/7 to all the things ;-)
As i love in my photography, to see how people react when they see my work (without asking them, but watching them together at some point and listen to their reactions without much talk.
Different eyes can see different things and maybe also have new ideas. Sometimes this are the most inspiring moments for other work or just how i could do things in a different way. It is so much fun when this happens. Unfortunately, this moments are so rare nowadays because of this "full" life we live without real living it. But it is what it is and we must take all the things we can.
I also like to take kids as a reference when i really have to give some feedback to friends, clients etc. Showing interes in their work then telling what i love about it and if is needed, some things that could make it "different" not necessary bad. And this way you can combine good/bad aspects.
Of course, it always depends on a lot of things like time you have, what you are looking at etc.
But the overall thinking is to be positive and go forward but not letting that person to not know when some things are wrong (this apply in the areas that you know what are you saying).
Cheers