Stress
Well, if Jonathan (the man who comes in everyday with Bluetooth in each ear and four phones for each of his work responsibilities) is stressed while waiting for his coffee because he only has five minutes to get to work before he gets fired, you're going to be stressed, too.
Here's the thing about coffee: People hate waiting for it. If they have to wait for it, it's your fault and they are not afraid to get angry at you.
Having a sleek businessman glare at you as he looks at his watch can cause a few heart palpitations. There will be huge rushes in the morning. As everyone gets grumpy, cranky, and tired throughout the day, they will come straight to your counter. But there will also be moments of relaxation when you only have to serve one or two customers before you can kick back and enjoy a cup of coffee yourself. Because you deserve it.