Consider that for Arabs the old school way would be using their left hand and sand (well, in more humid areas - water). Which is the reason you should be careful with your left hand while interacting with a person of that culture.
I think I like some paper between hand and ... more, than sand, ya knaw.
That's a society which had lots of hierarchy and very little social or even territorial mobility until very recently. And those people's ancestors were likely peasants who'd just live all their lives growing crops in very scary conditions.
I mean, I've heard these things about China and manners.
I've event heard maybe not so scary, but similar things about Russia and manners in the early XX century (since I live in Russia, I do believe they are correct).