^My logical reasons would be:

Since the plane is smaller than any other planes, it needs to be flying lower attitude than any other planes. Maybe due to air pressure, wind, temperature and such (someone which a physics degree, or aviations, other related degrees might explained it better me ). That explains why it only flying at 29k altitude. Moreover, since it can only fly at 29k or less altitude, therefore the flight will not be smooth. Due to clouds and such, the more the plane near clouds, the more it'll shakes, which creates alot of turbulence.

But yes I do like E-175 simply because it's small, and when you get on there, feels like you know everyone faces. ^