Quirky Japanese

So on my way home tonight I stopped off at the store because I needed to see if I could find all the ingredients I need for taco salad. I was successful except for ranch dressing which I knew that I wouldn't find, but one can hope. Now I had got some bread also, and maybe it was that and the chips or the fact that I had meat and vegetables too, that when I got to the register and paid he gave me two bags and said, "二つ分けて下さい.", or in other words separate your groceries into two bags. It was like he was trying to tell me you cant put the bread in with the meat and all the other stuff. It was so weird, why would he make it a point to say such a thing. It made me want to stuff everything into one bag and go back and say here is your other bag, I don't need it. But the fact was that I had enough that I had to have two bags, so what was his point?