The other day I was standing in line at my favorite restaurant, Chipotle. I realize its 80 miles away, but that's not too far to go for a burrito that brings you so close to heaven.
Anyhow, it was the dinner rush, so I knew there would be a wait involved. I walked in the door, and the line extended from the counter all the way to the spot I just filled immediately inside the front door. The next person to enter behind me would have had to stand outside. This is often the case at the Chipotle restaurants I've been to during the lunch/dinner rush. I began to wonder why the line rarely goes out the door, but rarely gets shorter then it is now? Even at Chipotles where they have more room for their lines, it still always seems to extend to the door, but no further. To be fair I have seen it extend out the door on occasion, but generally only on very pleasant days. So why is the equilibrium line length to the door, but doesn't extend past it?
Economics helps us analyze this problem. Clearly the marginal cost of spending even a small amount of time waiting outside in the cold changes the calculus sufficiently to deter people from waiting. I'm sure there are other dynamics involved, when the line extends outside, people's perception of the wait may increase versus if they do not see the line. Or maybe people that open the door and enter are afraid to leave for fear of feeling embarrassed. Therefore if you see the line out the door, you never approach.
Lots of possible explanations. Sounds like a dissertation topic. My testable hypothesis would be that in extremely cold or hot locales lines rarely extend outside, but they do much more frequently when the temperature is mild, and therefore the marginal cost of waiting outside is smaller.