If you want proof of exactly how much an aircraft's wings can bend, try this:
https://www.youtube.com/watch?v=Ai2HmvAXcU0
Someone once told me that if the wings were completely rigid, you would feel every tiny bump and turbulence would be much, much worse than it is now. This seems to make sense to me; the flexing of the wings must take a lot of the energy out of "irregularities" in the airflow.