Something that tastes zesty or tangy has piquancy. The piquancy of your dad's spaghetti sauce is what makes it your favorite.
Things with piquancy are exciting, either because of the way they taste or because they are fascinating. The mouth-watering piquancy of barbecued chicken is all about its flavor, and the piquancy of a thrilling ghost story is in the details. We can trace this noun back to piquant, "stimulating, pricking, or irritating" in Middle French.