There is a growing interest in the Human-Robot Interaction community towards studying the effect of the attitude of a social robot during the interaction with users. Similar to human-human interaction, variations in the robot's attitude may cause substantial differences in the perception of the robot. In this work, we present a preliminary study to assess the effects of the robot's verbal attitude while playing rock-paper-scissors with several subjects. During the game the robot was programmed to behave either in a polite or impolite manner by changing the content of the utterances. In the experiments, 12 participants played with the robot and completed a questionnaire to evaluate their impressions. The results showed that a polite robot is perceived as more likable and more engaging than a rude, defiant robot.