Until one has really found one’s footing as a person or an artist, it can be difficult to know what to say to someone whose work you’ve just seen and found deeply flawed.
The terrific advice columnist Cary Tennis answered that question in one of his Since You Asked columns in Salon. He quotes a story Jason Robert Brown told about being young and being invited with a friend by Stephen Sondheim to see Passion in previews and dinner afterward.
“They try to disguise their opinions but it is clear to Sondheim that they didn’t like the show, and it makes things very uncomfortable. Sometime after this very awkward dinner, one of them calls Sondheim to patch things up and this is what Sondheim reportedly said:
“”Nobody cares what you think. Once a creation has been put into the world, you have only one responsibility to its creator: Be supportive. Support is not about showing how clever you are, how observant of some flaw, how incisive in your criticism. There are other people whose job it is to guide the creation, to make it work, to make it live, but that is not your problem.
“”If you come to my show and see me afterwards, say only this: ‘I loved it.’ It doesn’t matter if that’s what you really felt. What I need at that moment is to know that you care enough about me and the work I do to tell me that you loved it … If you can’t say that, don’t come backstage or lean over the pit to see me. Just go home … Say all the catty, bitchy things you want to your friend, your neighbor, the Internet …
“”Maybe someday down the line I’ll be ready to hear what you have to say, but at that moment, that face-to-face moment after I have unveiled some part of my soul, however small, to you: That is the most vulnerable moment in any artist’s life. If I beg you, plead with you to tell me what you really thought … then you must tell me, ‘I loved it.’ That moment must be respected.”"
Also a great article from the NYTimes on what to say / not to say to someone going through severe health isssues.