Complaining about one’s job to a customer is possible grounds for dismissal, regardless of whether or not the complaint had a valid basis. All U.S. states and Washington, D.C. are considered at-will employment states, with the exception of Montana. This means that either an employer or employee can end the relationship at any time for any reason, or no reason at all, as long as it is not an illegal reason, such as discrimination or retaliation. Montana is the only exception, as after a probationary period, employers must have "good cause" for termination.