OK, here's the deal:
newish (to me) house. bathroom has two sinks next to each other, with
identical Moen faucets. both hooked up correctly. left hand faucet
works normallly, right hand faucet has hot water come out when lever
is to the right, cold to the right, i.e. backwards. but, i repeat,
it's hooked up correctly, just like left hand (not backwards) faucet.

hot water shutoff valve shuts off hot water and cold water shutoff
shuts off cold water, despite backwardness. hot water pipe gets hot
when hot water flows on either faucet. supply lines are not crossed up
under the faucets, i looked right up there. I pulled out the
cartridge, it looks symmetrical, pretty simple deal, a hole in the
left where the hot water comes in and a hole in the right where the
cold water comes in.

what the hell?