[the_mitsuhiko]

> in Excel's case that question "Do you really want to quit? You have copied large amounts of data to the clipboard." even occurs when you have a single cell's worth in the clipboard

That's not correct. You need to have quite a few cells in the clipboard for this to happen.

> But that's also a confirmation question that no one really understands

The dialog tells you exactly what it is asking for. It gives you three options: keep the app open, store the data in the clipboard, discard the data from the clipboard. I am not sure how a user could not understand what to do in that situation.

[wheybags]

Most users know about copy paste, but have no idea what "the clipboard" is.

[wizzwizz4]

Doesn't Microsoft Office still have a button in the bottom-right of the Cut, Copy, Paste section of the Ribbon (subtitled "clipboard") that opens a big Clipboard side panel?

[ygra]

Oh, indeed. I misremembered then. Seems to be that way in my ancient version already as well.