> I just changed the format of the column to "text" from "auto" and kept using it for my thesis work.

Yes, but for an existing spreadsheet, that won't work ex post facto. A spreadsheet in which some gene names have selectively been converted to dates won't be repaired by changing the column's data type. Such a remedy must be applied in advance of the import.

I was chewing through many datasets at the time, so I needed to do automation anyway (which was easier to do in R or PHP/Perl, given my background at the time). Even then, I still produced Excel output (with R scripts in an attached zip) when I wanted to share the final results with my PI and collaborators.