I used to work at a KFC and I think one of my favourite memories was during a very busy Friday night dinner rush I was up front service and older couple, maybe around 60ish. Someone in the drive through had apparently ordered 5 pieces of chicken breast, and one of the girls in drive through yelled very loudly WE NEED MORE TITS
The old people were not happy, but everyone else found it rather funny
White meat is "fast twitch" muscle and is used for short powerful bursts of activity, like the breast muscles, which are used for flapping the wings
Dark meat is "slow twitch" muscle and is used for longer duration activities like walking, hence the legs and thighs are dark meat.
Dark meat contains more fat and can be cooked longer without becoming dry. White meat becomes dry and tough very quickly if overcooked.
This only really applies to birds, mammals are made of red meat, which is like a combination of both fast and slow twitch and can do both sort and long duration activities
Dark meat is basically meat that's closer to the bone.
Compare to white meat, which is basically just the breast.
I prefer the dark meat, it seems to be more flavourful. I know a lot of people want nothing to do with blood and bones, and they prefer white meat because of that