I think Ribdog and Davesgrill have covered it all. But if you're making a chocolate milkshake, what's wrong with chocolate ice cream? Try it!... if you dare.
BTW, Baskin Robbins was my first job! I hated being an otherwise skinny, dainty girl with a Popeye forearm. And oh, when I was still new, I hated it when someone ordered a milkshake. There's a special trick to getting that metal canister off the machine while the little blades are still spinning, and if you don't master it, you end up with milkshake splattered left-to-right across your chest. People always ordered chocolate, it left the most obvious mark of my inexperience!