What if I helped build Glen's dam, because Glen convinced me that without the dam, the river would dry up before it got to me, and I'd be out of water? What if

What if I helped build Glen's dam, because Glen convinced me that without the dam, the river would dry up before it got to me, and I'd be out of water? What if Glen tricked everyone into not building dams of their own, because Glen promised to let other people use his water too, but then didn't actually honor his promise?