I'm somewhat used to sane operating systems. In other words, I'm used to the fact that, on an Apple machine, when you copy something—be it an image, or a string of text, or what have you—if you go to paste it, it will paste.
Even if you've been doing something else for a while. Even if you pasted it and then clicked on another cell in Excel.
Which brings me to Excel: for some inconceivable reason, if you copy something in Excel and run an operation and then go to paste it—it's gone! Disappeared in to thin air. Poof!
Now, I've had this as a known problem for years. But, believe it or not, people were whining about this in 2004, and even then saying that Microsoft knew it was a bug then, and didn't seem to care. So it's been going on for more than a decade!
(There's some technical nonsense about Excel having "move and copy" but a) that seems fixable and b) I can't think of any application where a user would want to have something they copied disappear.)
What rubbish. And I'd contend that Excel is one of Microsoft's better products.