And never try to deal with dates and timezones.

Or anything that looks like dates.

Gene scientists had to revise their whole naming scheme because Excel would see MARCH1 (Membrane-Associated Ring-CH-Finger Type 1), and ‘helpfully’ convert it into a date, rendering it useless (since it uses timestamps on the backend).

It’s bad enough that my data science course recommended against opening CSV files in Excel, because it would edit the file to do the conversion, even before you explicitly saving, mangling your data before you could process it.