Behavior of the Arrival: Most queuing models assume that an arriving passenger is a patient traveler. Patient
customer is people or machines that wait in the queue until they are served and do not switch between lines.
Unfortunately, life and quantitative analysis are complicated by the fact that people have been known to balk or
renege. Balking refers to customers who refuse to join the waiting lines because it is to suit their needs or
interests. Reneging customers are those who enter the queue but then become impatient and leave the need for
queuing theory and waiting line analysis. How many times have you seen a shopper with a basket full of
groceries, including perishables such as milk, frozen food, or meats, simply abandon the shopping cart before
checking out because the line was too long? This expensive occurrence for the store makes managers acutely
aware of the importance of service level decisions.