I not a good auditioner. I know I can do a marvelous job for a director once cast but it's getting the part in the first place that I have a hard time with.
More difficult still is being the director doing the casting. Especially if it's kids auditioning. There's always something slightly unique about each kid's audition. It would be such a delight to work with each kid in a spectacular role. But there aren't enough spectacular parts to go around. As a director, I can only hope the kids who are cast will make the best of their parts whether or not it's ones they wanted.
Directors tend to quote Alexander Pope, "Act well your part; there all the honor lies," or Stanislavsky's "There are no small parts, only small actors," in trying to encourage actors--especially kids and youth--to feel good about a small part they ended up with. But disappointment is disappointment and it doesn't go away with a good quote. I always do the best I can for any role I'm cast in but I might be disappointed for a day or so if I didn't get the part I hoped for. So I feel disappointed and then it goes away and I enjoy the rest of the process. That's life in general, isn't it?