No such thing as a small part, only a small actor. (meaning 'small' in outlook)
This is a theatrical adage or maxim I was party to learning many years ago. Sometimes in casting should one be lucky enough to get a part in a play, it may not be the largest, the main part or the sexiest part, but a 'bit' part - the servant, the spear carrier, the almost walk on or generally a tiny role in a production. Over the years, and particularly when I was with Derby Theatre In The Round I was often offered a diddy role to play when, as a young-enthusiastic, but naive actor, I really - heart of hearts - would have liked to have played the lead. Sometimes you are just not right for it and deemed keen, but inexperienced. It seems a tough choice at the time. However, it is often correct and strange as it may seem at the time, a good chance to learn.
Sometimes such a role can come out of the blue and be a great opportunity to be involved in a top class production and be just as vital to the piece as one of the main roles. In the Lace Market Theatre's recent production of Festen I was offered such a role (Kim the chef) because the original actor was alledgedly unreliable and unavailable a week before the production opened. My experience and reputation that I have built up over many years of theatre experience allowed me the opportunity to say 'yes' to such an offer and it proved to be one of he most rewarding small parts I've done in years and allowed me to meet a whole new bunch of good actors and work with them.