Personally, I don't like having Excel create three worksheets for me every time I make a new workbook. It seems like a random number, and I quite often either need more or less. I've set Microsoft Excel to default to only create one worksheet when I make a new workbook.
Here's how you can change this on your own computer, so that Excel will open however many sheets you want. Go to the 'File' tab, and click on 'Options'. Now look in the 'When creating new workbooks' section, and you'll see there's a 'Include this many sheets' option. This is where you can type in any number between 1 and 255. Click the 'OK' button when you've finished, and you're all set! The next time you create a new workbook, Excel will put in the number of sheets that you specified here in your Excel Options.