Many conflicts, disagreements, and ill-feelings in small groups are the result of ambiguity. Ambiguity generally comes from assumptions the manager assumes that the employee knows how much money is available for a project; the parent assumes that the child knows when to come home; the teacher assumes that the class has learned something basic to the subject at hand. When one person assumes something, there is almost certainly going to be ambiguity that is going to lead to confusion on the part of someone else and an unexpected outcome.
For instance, a parent has several packages to be delivered to various people. The parent leaves instructions for the child to deliver each package to a particular person, saying that the first package goes to a grandparent, the second goes to an aunt, etc. However, the parent counts from the left, and the child counts from the right, so the packages wind up with the wrong people. The parent may blame the child for delivering the wrong packages, but the parent is actually responsible.
In a business situation, two departments may hate each other if one has to deliver something to the other but the item has not been sufficiently defined. As long as there is uncertainty, there will be interpretation, and interpretation often leads to unwanted results. If a finance department needs a report in a certain format but just asks the shipping department for a list of customers and items shipped, the report is likely to show up in a format useless to finance. In such cases, the finance manager will most likely belittle the shipping manager and the finance employees will believe that the shipping employees don't know what they're doing. Again, bad feelings result between the two groups.
It's generally fairly easy to minimize ambiguity: State what you want, ask the other person to confirm, and restate until you reach agreement. Depending on the situation, this may take a little time or a lot of time, but at the end you're much more likely to get what you want. Of course, the amount of effort you spend defining what you want should be proportional to its importance.
Especially in cases where you have some control over the situation, you can help eliminate ambiguity simply by taking the time to be as specific as necessary. Eliminating ambiguity will help eliminate the irritation and suffering that often occur in small groups.