I do notice them. I always stop and say Hi to the guy at Carrefour who checks in your shopping bags and I always give him 10QR when I collect my bags. I know the security guys in Virgin, the guys in Starbucks and I take the Karwa bus with the workers and know many of the Dukhan road guys by name.
Often it is not just about tipping but more, for me about looking people in the eye, smiling, acting as if they exist and being one human to another to them. Even if that means sitting next to them, eek a man! eek, a bit sweaty!! I have had a few arguments with people here who say I am "spoiling it for the rest of them" because once a week my Indian cleaner spends half an hour on my Skype to his wife, parents and children.

Personally I like having a cleaner and living in a country where there is a service industry. The divide between rich and poor is the way the world currently is and it's not my, or Qatar's fault. There is a difference between service and slavery and many people forget that here.