I would say, though, that the mattress is by far the most annoying. It's a floppy object with handles - if it even has handles - that are placed in arguably the word possible location:

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     |     |
    [|     |]
     |     |
    [|     |]
     |_____|

This is fine if you're carrying your mattress pallbearer style down a wide open hallway, with it orientated the same way as it would be laying on your bed. But in reality, most people move to places with hallways, or stairwells, where it would make the most sense to rotate it 90 degrees about the longest axis - and the best way to carry it then would be with handles here:

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      _|_|_
     |     |
     |     |
     |     |
     |     |
     |_____|
       |_|