Communication between the departments is key to a sign business' survival. When the management team realizes this, it will become a priority for all departments. The sales department may have had no idea how many projects were on the docket. The production department probably didn't realize how much business depended on customer X and how much stress that customer's unhappiness was causing the sales department. Though all of these examples of how companies don't communicate might seem pessimistic, you do not have to talk to too many sign professionals to hear stories of similar scenarios in their shops.
Cranky workers are unhappy workers, and unhappy workers are neither efficient nor effective.
Better communication can help. The time used to improve communication is time well-invested. The sales and production departments might already communicate really well with each other, but they both need to know what long-term goals were developed by management team. Your current customers and potential customers. If the word gets out about internal conflict, if they see the conflicting circus in action, or if they don't like the kind of treatment they receive, customers will go to the sign shop down the street.