Why does food from the same chain restaurant taste different by location?

Imagine this, you’re away from your hometown and you’re craving your favorite chain restaurants’ chicken soup. You go in, sit down, place your order, wait in anticipation, and when your server finally places that steaming bowl of yumminess in front of you and you take a bite.  it tastes nothing like what the location at home serves. Now wake up from that nightmare, because it rarely ever happens, and there’s a good reason why.