Spent 3 weeks stuck on one Excel formula for my quarterly report and finally cracked it with a VLOOKUP and a prayer
Kept getting a #N/A error on a 900 row sheet and it turned out there was a hidden space after every name in column A, so typing TRIM into the formula at 11pm on a Tuesday finally fixed it, and I'm curious if anyone else has lost a week of their life to invisible characters in a spreadsheet.