Can you do me a favor?

This is the conversation that I hear every day in my house. "Mommy, can you do me a favor?" usually followed by "Can you get me some milk?" I honestly only asked Collin to do me a favor once and ever since then he is
constantly asking for a favor. It was cute at first but now I hear him say it ten or more times a day! I'm hoping that he'll just start asking for what he wants instead of asking for a favor first.