Taking Responsibility

Responsibility, it's a word that we've been hearing for years, especially since college. While we're constantly told that we need to be responsible and take responsibility, what should we be taking responsibility for? How about our actions? I was reading an article, written by a student, about taking responsibility for our actions regarding the environment. Face it, it's our fault that desertification, water management problems, and forcing animals & plants out of their habitat.
This student felt very strongly about consequences of actions and taking responsibility for decisions we make. From that I started thinking about everyday decisions that we make and what comes from them.
I recently sat down with a friend who is directing a play. One of her actors, after being notified of the dates of the performance during his audition about 4 months ago, told her that he wouldn't be able to make one of the performances due to religious reasons, about 3 weeks before the play was set to open. By doing this he hindered the whole cast and ultimately decided to leave the show and had to be recast. Where is his responsibility? What should his consequences be? Was it the director's responsbility to take in account this particular religious holiday or was it his to realize a performance was on that day or was it both?