In your copy of Excel it is January 2nd.
In most other countries, it is February 1st.
But here's Excel's trick: you type in 01/02, Excel interprets that as January 2nd and switches it to the underlying OLE date format (some number in the 40000s). Ship that Excel file across the ocean were they would write Jan 1 as "02/01", and it shows them the date as "02/01." Excel uses your local date format preferences.
This is one reason why it is important for Excel to convert the raw input to another format. I'd probably prefer that it didn't touch it for CSV files, but I get it for .xlsx
