Use these dialogs sparingly as they tend to interrupt the user. If they are used too often, users tend to stop reading dialogs and clicking any button to get rid of them. When writing the copy, summarize the action that needs to be confirmed in one sentence and accompany it with two buttons allowing the user to take action. Avoid using vague description button labels like "Are you sure?", "Yes" and "No". Instead, use clear language so the user has no doubt about what will happen next, for example: "Delete this user?" with "Cancel" and "Delete".