Our Roomba loves to get stuck under certain pieces of furniture and the low overhangs of our kitchen and bathroom cabinets. It just wedges itself in place and gets jammed, eventually erroring out.

If it doesn't do that, then the other annoying thing it sometimes does is drive off into a bedroom and go underneath our king-size bed, then "dies" (runs out of battery) somewhere in the middle of the bed area, which makes it very difficult to coax out. Neither my arms nor my wife's are long enough to reach it; I generally have to use a broom handle or such to shove it closer to one side to pull it out.

First-world problems, right?