Why does excel sometimes get stuck on a group of cells

"Why does excel sometimes get stuck on a group of cells?"

"Why does excel sometimes get stuck on a group of cells and it’s very hard to get it to click and sit on only one cell at a time?"
This was a question I answered on Quora.
It's something which has plagued me in the past, so I thought I'd post the ridiculously simple reason why here:

When this happens, what you may be experiencing is Excel’s Extended Selection functionality.

You may already know that if you hold down the CTRL (Control) key while you’re selecting cells, you can select a range of cells which may not be next to each other.

Neat.
And if you select one cell, hold down the SHIFT key, then select another, you’ll select all the cells in-between.

What Extend Selection mode does is allow you to achieve the same kind of selection the SHIFT key does without having to use your mouse.

It’s a feature for all those keyboard freaks out there (like me )

Try this . . .

1. In Excel, create a new workbook.
2. Select cell B2 in the top-left corner of the worksheet.
3. On your keyboard, press F8.
4. Now press the down-arrow key 10 times, and then the right-arrow key 5 times.
5. You’ve just selected 66 cells.
6. Press F8 again to turn Extend Selection mode off.

So, if you find your cells getting ‘sticky’ (for lack of a better word), check Excel’s Status Bar in the lower left corner of the screen:

If it says Extend Selection, simply press F8 to turn it off.