Have you ever seen a clown car packed full of clowns? It might seem hilarious to see them all come out of there, but you would hate for people to feel packed too tight inside of your establishment. In fact, having too many people in your business would be a major safety risk, and it would be breaking the law.
There are guidelines for how many people can occupy a business at a time, known as the occupancy load. In the past, there have been terrible accidents due to these guidelines being ignored. When there is a fire or similar danger, everyone trying to rush out at once can do more damage than the actual fire. There are also incidents when floors that were overloaded have given way, dropping people several feet and causing death and injury.
Depending on the size of your building, the exits available and the type of establishment it is, you will have a different ratio of persons per square feet, and it is very important to pay attention to that number.