You say cultural differences, I say respect. When I come to the theatre I expect to watch the performance and the performers I paid to see, not to appreciate the variety of ways people are experiencing the joy of art. I want perfection too and I want the performers to want to show me their best. Critisizing someone for how much they, in your subjective view, suffer (or, in my subjective view, care about what they do), don't enjoy themselves, don't smile enough, etc is strange. The behind the scenes work is what it is - it's not for you to see and if you do see it, it's not for you to judge. Do judge the performance though.