Most of them are polite and if they kept you waiting they normally apologize for that. We have dealt with many of them and not even once treated the way the other Arab nationality will do (no need to mention where they are from). I have seen Qataris many times when we go to City Center, there are some ladies who are well dressed, looks very rich, while we were at Starbucks. she called the cleaner and gave him bunch of money passing it to his hand, just like that!