I'll bet I can make your left eye twitch.
Are you ready?

A "large" amount of information.
Bitch, my computer has 128 gigabytes of RAM. It's a tiny god. The fact that I have as many as 100 cells copied to the clipboard (which is the threshold that triggers this stupid message, if you've ever wondered) is not even a rounding error. I'm sure this was marginally important in 1982 or whenever this was first coded into Excel, but today my computer could lose an entire megabyte of memory or maybe even ten down between the couch cushions and neither of us would notice.
There is still no setting to disable this dumbshit message.