I'm just stating what I see in and around Doha. Consensus is that Arabs see service workers as subclass and tend to treat them with less respect than others. I know Islam teaches a different attitude but is seems that more affluent Arabs forget the teachings. I tip no matter what part of the world I show up in. This is only a personal oppinion but I feel that no matter what class person/worker you are you deserver respect and appreciation for the service that you provide. If i like the service I tip... If i dont like the service I always provide an explination for the distatisfaction.