Johnston's Constant, immodestly named but what the hey: The near-Universal desire for a Universal standard of taste, which nevertheless doesn't exist.
Johnston's Constant has two corollaries:
Corollary no. 1: The "You like that?!?" corollary. Amazement over the fact that other people lack one's own good taste.
Corollary no. 2: The "What can I do to make you love me?" corollary. The wistful desire for some ironclad and indisputable method of pandering to everyone at once. A fond but futile hope. The fact is, no matter how hard you try, no matter what you do, some people are going to like it, some people are going to hate it, and some people are going to be indifferent. C'est la vie.