Excess, the artificial and the desert.
Sixty years ago, Abu Dhabi was a pearl-fishing village on a sand island. Oil, discovered in 1958, and the federation of the seven emirates in 1971 under Sheikh Zayed changed everything: in two generations the city became a capital of glass towers, museums imported from Europe (the Louvre Abu Dhabi, under Jean Nouvel's dome), palaces like Qasr Al Watan and artificial islands. Everything is recent, everything is huge, and it's fascinating to see with your own eyes.
But what struck me most is what was there before: the desert. An hour's drive away, red dunes stretch as far as you can see; you drive over them in a 4x4, walk the ridges at sunset, sleep at camp around a fire. That contrast is what makes the trip great: the skyline from the sea in the morning, the complete silence of the desert at night. Less contact with locals than elsewhere, but a thousand things to do.