I remember older versions of Excel had a user preference for how many sheets to put in a new workbook. The default was 3.
I found it annoying when I got spreadsheets from people where they used a single worksheet, yet the presence of sheets 2 and 3 made you think there was stuff on there you needed to search for. I would always delete the extra sheets and had set my preference to 1.
I think MS did set the default to 1 in later versions of Excel.