Single VS. Double

Yesterday I stumbled into McDonalds for my break at work. I stumbled because as I was opening the door, somebody on the other side was opening it as well. I lost my balance and that's the story. I only had a couple of bucks on me and I didn't feel like using my debit card. So I had this dilemma, should I get a single cheeseburger for .99, or for a penny more, I could get a double cheeseburger. So I went for the double. The end.