The fat in the fried chicken (lard, if you are doing it right) will end up coating your tongue. Acid from the lemon both helps cut the fat some and let you get it down your gullet instead of coating your mouth, and it also activates your taste buds, giving it a more balanced taste.

This is why when you get a german schnitzel (fried cutlet) it will usually come with lemon, especially if it doesn't come with a gravy or sauce.

Beer with chicken is similar -- beer has the additional help of carrying alcohol soluble flavors (the chicken has its own fat and water to act as solvents for those flavors.)

Never had it, but I'm sure Chinese Lemon Chicken would beat it. Was never a fan of 'sweet'n'savory' before, but I'm convinced....enough I learned how to make it.

Because deep fried anything is good. And lemons a pallet cleanser so you can eat more.

Like how milk helps you eat more cookies