Final answer:
Complexity is not a characteristic of a well-designed service system; in contrast, simplicity is usually preferred for ease of use, maintenance, and error reduction.
Step-by-step explanation:
When evaluating the characteristics of a well-designed service system, aspects such as efficiency, reliability, and flexibility are considered to be vital. Efficiency implies that the service system operates with the minimum resource usage and wastage. Reliability is the service system's ability to perform its intended function under specified conditions for a particular period. Flexibility denotes the system's adaptability to changes in demand or the environment. However, complexity is typically not a characteristic of a well-designed service system. Simplicity is usually favored over complexity, as a simple system is easier to use, maintain, and less prone to errors. Hence, complexity is not a characteristic of a well-designed service system.