Apple's failures, according to me...
The Pippin Video game system 1995, $599, Internet connected, took 10 minutes to receive a chat message.
The Lisa - Innovative for 1983, Cost $10,000
iMac/Powermac G3 Mouse - Still have one. You think the mighty mouse is bad?
G4 Cube - 2000, way too expensive and had an external power supply that was bigger than the machine.
The Quicktake 1994, 0.3 megapixels, 24 pictures, slower than molasses, $750
You may see the following on some people's lists:
Macintosh TV, Newton and Mac Portable.
They were not terrible products per say, just way ahead of technology at the time.
The interesting thing, Steve Jobs was not around for most of Apple's failures.