In October 2020 the UK government lost thousands of COVID test results because they hit the limit of the maximum number of rows in an Excel file. This is but one of many, many mistakes made all around the world because of spreadsheet abuse. Matt Parker is a long-time spreadsheet fan. His stand-up routine about spreadsheets has over 2.5 million views on YouTube. But he has also investigated the incredible ways they can go wrong for his best-selling book Humble Pi. In this session Matt will look at some of the top #VALUE! greatest spreadsheet mistakes as well as other times mishandling data and maths has led to disaster. Come armed with your own spreadsheet horror stories to share!