the disk-eject menu item that was in the OS for 10 years which all Mac users knew to avoid because of the disk swap nightmare.
Apple never bothered to fix the menu item and it was just a useless pimple on the Interface, or worse if a newbie used it and got caught.
I feel the need here to defend what was actually a solution by Apple, it could be argued it eventually warranted removal, but never fixing.
Let's imagine your working on a Mac Plus, it has 1MB of memory, no disk drive, and a single disk 800K floppy drive. You've just finished your novel, and it's a whopping 700K; you save it to your floppy drive. Now you need to make a copy for your editor (who's very modern and accepts electronic manuscripts). You can't load the entire file into memory along with the OS and an application, so you open the disk's window and then eject the disk; a ghost of the original appears on your desktop. Now you insert a new floppy disk, format it, and drag the file from the open window to your new disk. MacOS prompts you to insert the original disk and buffers most of the file into RAM, it asks you for the second disk, and writes the data out, the first disk again and copies the rest of the file, the second disk and writes it all out. You can now 'put away' the first disk from the desktop.
The features down-side was understanding what "Put Away" (ejects a disk and removes it's existence from memory) and "Eject" (ejects a disk) did. Many new users got this wrong. Apple could probably have done a better job on documentation or naming here, but technology wise it was a good solution to a problem. (Keep in mind it was invented for the 128, which had 400K of floppy storage and 128K of memory.)