Matt, there are three classes of requirements.
Need to Have: Those skills, materials, and abilities absolutely required to accomplish the mission. Without them, it is impossible.
Good to Have: Those skills, abilities, and material that enhance mission accomplishment. You can get it done, but the good to have stuff sure helps.
Nice to Have: Stuff that has no bearing on whether you can or cannot accomplish the mission. It may give you a warm fuzzy, but you can definitely do without it. Manners, and the knowledge of which fork to poke at the salad with, fall into the nice to have category.