I hereby hate the people who programmed Excel and how it deals with date formats.
This error warning makes absolutely no sense. Sure, there are a ton of date formats. But the source file, which I made myself, is just a CSV file. The destination file is a brand new empty Excel file. Four years? You are kidding me. Approximately? What? This is not acceptable.
Edit: Aha! So this is what is going on. Not at all acceptable, since it means that Excel is interpreting the text as dates when I just want it to passively see everything as text. Microsoft has made Excel overdo it here, and it is not helping.
