h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I think what you are describing is a perfect example of McMurphy's Law of fast food. Another example of this law (and it doesn't just apply to McDonalds, but to all fast-food outlets), is that which states: No matter which queue you choose to join - it will always be the slowest moving. The precise slowness will be in direct proportion to how little time you actually have, ie. if you have 5 minutes to catch your train - the queue you are in will take six minutes to clear. Frustrating yes, but these are forces of nature that we're dealing with.