Speaking at a recent forum on productivity and service excellence, SMU Behavioural Sciences Institute Director Professor David Chan pointed out that implicit in comments referring to dissatisfied customers as ones with "rising expectations" is the thinking that the customer is being unreasonable. Such thinking percolates down from boardrooms to the employee who has to respond to a complaint, he said. The employee assumes unreasonableness – even when the customer's feedback is legitimate – depriving the company of the opportunity to respond constructively. Rather than peg customer expectations at an unknown, unattainable level, Professor Chan suggested that companies try to identify the different levels of expectations a customer has. Because customer expectations are so easily shaped by environmental changes, which may be out of any individual company's control, trust is important to tide a company through fluctuations in customers' expectations, he added.