The more the mind is in contact with any mental quality (such as calm or joy), the more familiar it becomes with it, and the more familiar the mind becomes with that mental quality, the more quickly and easily it gets it.
Familiarization is the other key aspect of meditation. Familiarization is so important in meditation that the Tibetan word for meditation literally means “to become familiar.”
from “Joy on Demand: The Art of Discovering the Happiness Within”
by Chade-Meng Tan