Theatre Etiquette - Multiple Shows?

Just wondering what everyones opinion is on taking on more than one show at a time in community theatre? Examples: A Director or Musical Director taking on two projects and then splitting their time between the two (OR neglecting one in favour of the other!) A leading actor accepting a role in another production then having to divide their time between roles. My opinion is that you need to commit to one project, so that you can make the best show you can and put all your effort into it. It always seems that others have to pick up the slack for those that accept more than they can handle? Just my opinion and I am interested to hear what others think, as it seems a lot of people now have more than one project going at once. I cant imagine doing this, as once Im in a show - I can only think about one role, one set of songs, one set of dances and so on????