Perhaps it's the location that I go to. It's right next to a bus terminal and near a couple of major roads used by commuters. In other words, their customers are bound to be in a hurry. I'm also basing my assessment on where I see people in the store. For that location, milk is conveniently located and there is a lot of traffic in that part of the store. Motor oil is not conveniently located, but it doesn't seem to be an area that people frequent much either.