This is a question that I am asked at least once a month by a patient. Usually they are seeking a reassurance that they are not badly behaved. Often dental procedures can be difficult for patients to sit through, especially if their mouths are small and the procedures are lengthily.
Often a dentist will have to remind the patient to keep their mouth open widely to fit the tools in "or ask them not to move while they are being worked on. This certainly doesn't make them a bad patient!
Although there are patients whome are more difficult to treat than others, it certainly doesn't make them bad patients. Sometimes they do require a dentist to schedule more time or more visits in order to treat their problems and often dentists may not feel they are being as well compensated financially when treating these patients.
Sometimes dentists can become resentful of patients that routinely require more patience and time to complete dental procedures. It adds to the stress of a day since it can cause a dentist to run behind schedule or even make it more difficult to achieve what the dentist feels is an acceptable result.
If I do have a patient in my New York dental practice, who I routinely have difficulty completing procedures in my normally allotted time slots, I will schedule them for longer appointments and sometimes I am forced to alter my fees for their treatment to allow for the extra time needed to complete their treatment.