Planes have to be sturdy and flexible to handle the environment they spend most of their time cruising in. This is probably nothing next to the turbulence planes are expected to shrug off while maintaining a ground level environment eight miles up for decades of service life.
I wonder if the passengers would even notice if they weren't warned to expect it. From what I understand, they don't let the front down until they're nearly stopped in these situations. You can tell when the nose drops, and it barely seems to register aside from the scraping noise and a little shaking.
