uhhh huh. Let me guess, some of them were nice to you, to your face.
Here's my assessment for the four countries I visited regularly:
The Lebanese pretty much lied all the time, even when the truth would have been in their best interest.
The Syrians weren't much better, but their lies were always more obvious. Somehow they seemed a little less slimy.
The Jordanians were the best (or least bad). Rather than lie they tended to avoid direct questions and change the subject, unless of course it was something they wanted do or tell you anyway. I can honestly say they were the only ones who always did what they said they were going to do.
As for the Palestinians I had very few actual face to face dealings with them. I only went to Gaza once (which was enough for a lifetime; what a dump).
Bonus assessment (since they aren't Arabs): The Israelis were a mix. The ones you developed a personal relationship were usually good to go. If they didn't know you well, then all bets were off - some of them were better though about screwing you to your face. The Israeli's BTW, would have reversed my order with regards to the Syrians and the Lebs, and held the Jordanians in higher regard than I did. To them, the Palestinians were not worthy of much discussion.
And yes, all the Arabs were nice to your face; I drank a lot of Chai.