Even the most conscientious housekeeper is going to come into contact with a dissatisfied guest. It's part and parcel of the work. An effective interview should include examples of how the housekeeper reacted to disgruntled customers in previous jobs, or, for newcomers to the industry, what they would do when faced with an angry customer. You want to hire an employee who knows the value of listening to a customer's grievances and working to resolve his issues.