i have a no seafood leftover rule. i cant get it past my lips when things get fishy. so i call that my least favorite.
fav? lasagna!! i think it gets better the next day.
i do however have braised beef shortribs in my fridge right now. i cook it the day before so i can cool it and pull off the fat-cap. but this doesnt count..i dont think it is leftover yet.