Within my first half year of working in a startup, I got to touch invoicing code and thought I had written tests for every occasion and had removed all bugs. A

Within my first half year of working in a startup, I got to touch invoicing code and thought I had written tests for every occasion and had removed all bugs. A month after the code went through reviews and more testing, and was put into production. Another month later, more than half a million dollars is missing. After figuring out what went wrong, the issue was quickly fixed and corrected invoices were sent out. My point is: While it's not like brain surgery, in that every mistake is deadly, some mistakes can have devastating consequences.