I have the occasion to sit in a Starbuck's almost every day. I have noticed there are rush hours sometimes. It's like hundred of people decided to buy something at Starbucks at the very same time. They rush in, the line becomes longer and longer, and about 15 minutes later they disappear until the next rush hour starts about 45 minutes to 2 hours later.
Also there are days when many people choose to stay inside of the Starbucks for like 30 minutes to 2 hours. One week later, the Starbucks might be totally empty under the very same conditions (depending on the day of the week, weather and temperature, school holidays, etc.).
To me it seems that this process is totally random, at least I don't see any connections. I'd like to calculate how possible it is that my Starbucks will be full of people today.
Are there any models for this or ways to calculate the consumers' behavior?