That's led to one of the most marking bug I've had As a kid, I developed an education in software in visual basic. The software I had developed worked fine on my computer but when I installed it to any other computer it would fail.

It took me a long time to find out the issue. I was saving files in CSV using standards methods from Visual Basic. By default, the decimal separator in French is a comma. When Visual Basic saved a number in the CSV file, it saved it with the comma and without escaping or quoting. When the file was read back, the decimal part of the number was thought to be another column...

The only reason, it worked on my computer is that I had set up the decimal separator to a dot there because I found it more readable.