VIP cars. Yes, they do prey on (rich, tired, confused, jet lagged) westerners. Gotta be careful
Usually drivers will ask you whether you want the fastest or shortest route, if there's likely to be a significant difference. A Sharjah driver was at pains to explain the options to me last night; I sensed someone had given him a hard time recently.
Did your guy seem like a newbie ? I generally assume cluelessness rather than intent, or a genuine desire to do the right thing for you. These guys are strictly policed and shortages, etc come out of their own pocket.
11km extra would cost you US$5, but you may have avoided at least one toll, maybe two, so that's $2.50 back.
But yes, he should have explained.
What time of day was this ? Rush hour ?