What are the sources of customer dissatisfaction?

There are many, many sources of customer dissatisfaction. 
Some are common to all businesses while some are specific to various business types. 
Perhaps the main sources of dissatisfaction that are common to all types of firms
are:

• Quality of product.  If a product does not
  meet the consumer's expectations, consumers are very likely to be dissatisfied.  This
  can be true of a customer whose new computer does not work right as well as of a
  customer who does not like their restaurant meal.


• Speed
  of service as compared to expectations.  If customers have to wait longer than they
  think is reasonable, they will tend to be dissatisfied with the company.
  


• Responsiveness of customer service.  Customers who try
  to get help or to register complaints tend to become dissatisfied if they feel the
  company does not respond to them in a way that shows caring.  They feel they are being
  "brushed off" and become very upset about
  that.

There are many other causes of customer
dissatisfaction, but these are three of the most important.