tl;dr:"I was 6-months into my first real developer job, trying to fix a bug. Our application would sometimes insert rows with an invalid “foreign key.” Of course, the bug was only seen in production, so I had a production MySQL shell open to see the bad rows."
tl;dr:"I can’t tell if the author was being clever or if it was a particularly lucky typo. Either way, I will continue putting - at the beginning: [-,.]. But if you feel the need to send someone down a rabbit trail [,-.] is an option for you." Paul discusses how arrived at this conclusion.