I have heard that Arabic / Islamic society is much more family, neighbor, who-you-know oriented versus western society trusting more the rules of some authority, even if not personally known to you. Even for example, mundane things like if you need your plumbing fixed, you don't look up the yellow pages, you ask your friend to refer someone.
Does this lead to "favors" being more acceptable, like as a gift to someone you know for having helped you? Interpreted in a more charitable way, bribes/baksheesh are an expression of gratitude (though now an obligation of doing business)?
You start to think such factors must be ingrained in a people's mentality, because otherwise, why don't we just declare laws that make this sort of practice illegal and everyone is happier?