Taking a look at the front cross section showing "Wing Flex in flight" is interesting. I had no idea the carbon composite wings flexed so much that the wingtips are higher than the main body of the plane during flight.

It's flex or break. The wings hang from the plane body when it is on the ground. But when it is in the air the plane body hangs from the wings. That's a large amount of weight. It also shows you just how much lift those tips generate.

You can see this in flight. It's pretty obvious if you're sitting near the wing.

sometimes I'll get a wing seat to watch them flop around. In turbulence they flex at least a couple feet

The emergency exit row is also great for cheap legroom. But sometimes the seats don't recline

Yeah, the Dreamliner looks beautiful during takeoff. You see the wingtips slowly, but steadily rise above the plane.