Well you know you're really not doing the Master-Cleanse if you take in anything besides what the book prescribes (such as chicken soup).
Why are you doing this at all? It always helps me to remember my goals when I get tempted or bored. If you don't really know why you're doing it, then you'll probably have a hard time staying on it.
Re: watching others eat. I used to have a hard time with that too, but this time around for some reason, it doesn't bother me. I guess I'm more resigned to the fact that I'm not going to eat for 10 days, the food will be there when I go off the MC, and that's all there is to it. But I do try to avoid eating situations, which is hard with a family to feed, I know.