Christine Rooney asks: >Is it appropriate to go back stage after an evening's performance to meet >the guest artist? I'm a bit shy. I don't make a practice of going backstage. However, at times a performer has moved me very much, and I want to tell him or her. I figure they get a lot of negative criticism, so why not give them something positive as well? I try, however, not to gush and to make my praise as specific as I can. For example, the pianist Susan Starr gave a earth-pounding performance of Bernstein's Symphony No. 2 "Age of Anxiety." I was just about alone in giving her a standing O. One couple sitting near me asked how I could like such ugly music enough to applaud beyond politeness. I said I found it powerful rather than ugly and that there was a lot of boogie-woogie (which I like) in the piano part. So I went backstage and told Ms. Starr how much I thought she swung. Two years later, I went back again to congratulate her on a wonderfully delicate and fleet performance of the MacDowell second piano concerto. Antje Weithaas, the young German violinist I've raved about before, I also talked with backstage - briefly, since she doesn't speak English and my German isn't what it was 20 years ago. In fact, I like to keep these encounters as brief as possible - just long enough to let people know I was paying attention and liked what they did - so it doesn't tax either of us unduly. Steve Schwartz