Cavity suggests a negative connotation. Whenever you think about cavity an image or an issue presents itself. The first image includes dental visits. Particularly when I was younger. Back then the drills were run by steel cables. Very Kafkaesque.
Other cavities suggest returning from opium countries. Planes. Searches.
Another major time you think about cavities would be where your organs reside. Normally they resemble a good next door tenant. Quiet, restful, innocuous. The moment you have to take them aside and tell them to quiet down, well the good relationship starts to deteriorate.