As a user
I want to create an account with 0 starting balance
So that I can deposit my money from a blank slate
As a user
I want to be able to deposit money into my account
So that I can store my money safely
As a user
I want to be able to withdraw money from my account
So that I can access my money easily
As a user
I want to be able to see my bank balance
So that I can manage my spending
As a bank manager
I want to prevent users from withdrawing more money than they have
So that I am not giving away free money