I think mine had to be when I was working with SQL and Lua. I was attempting to store some ints into the database but kept having it fail randomly. It was a 50/50 chance that it would succeed or fail. I tried reading errors (Limited on what I could see) after a while (Almost 3 days, since everything I could think of didn’t have issues and was completely lost) I realized the system another developer setup returned either string or int, thus it causing it to error out when I gave it a string. Once I added a tonumber statement, all my headaches went away.