A customer placed a call to a mail$-$order catalog firm. Several times the customer dialed the phone and received a busy signal. Finally, the phone was answered electronically, and the customer was told to wait for the next available operator. Although it was a $1-800$ number, he found it annoying to wait on the phone until his ear hurt. Yet he did not want to hang up for fear he would not be able to get through to the firm again. Using the problem statement $$What makes a customer wait?$$ as your base, brainstorm to create a cause$-$and$-$effect diagram. Once you have created the diagram, how would you use it$?$