Before we had a car we would do a combination of walking and taking a bus to the office we met in for church. It worked out pretty well except that we would be all ready to go home around 1:30, Elise's nap time, and we'd always have to figure out how to feed her (and ourselves) and keep her awake until we got home. So on the way to the bus stop we usually grabbed a durum (a chicken sandwich that is wrapped in flat bread) and ate it as we walked/rode the bus home. Sometimes people would give us strange looks but we always assumed those strange looks were because we were foreigners. Being Americans in a sea of Turks, we're pretty used to all sorts of looks. Anyway, eventually we'd get home and put Elise into bed, her tummy full of durum.
One day James' friend Serkan was telling James about fast food being sin.
James: I don't understand.
Serkan: The only reason for fast food is so that you can eat it fast, like while you're walking.
James: Okay, but I still don't understand.
Serkan: Eating food while you're walking is sin.
James: I don't understand
Serkan: If you eat food while walking, a little piece might fall on the ground. And then if someone steps on that little piece, especially if it's bread, that's sin.
So, fastfood restraunts promote eating while walking. Serkan boycotts them. They are basically dens of sin.
Aha! So that explains those bad looks we would get while eating on the bus rides home! We've obviously got a lot to learn.
P.S. I'm not the only one I've ever seen eating while walking. Sometimes Turks do it too. So while it's sin, and there is a chance you might spill a crumb which might eventually get stepped on, some people just don't care and even those who do occasionally take the risk when they're hungry.