|Buffers at Paddington Station|
To hit the buffers is to come to a sudden and unsuccessful end. It implies a massive force moving at speed - like a train with brake failure, about to overshoot the station. Good thing they installed these big ones ... just in case.
More commonly in rail transport, though, "the buffers are projecting, shock-absorbing pads which, when vehicles are coupled, are brought into contact with those on the next vehicle" (wikipedia). Shock absorbers.
As well as it's chemical usage, buffering exists in data ... won't go into that just now ... and "hitting the buffers" has often been used as a catchy phrase in articles about economics.
Buffing - polishing - may require a machine, a buffer -
Which leads me to wonder about the origins of "in the buff" ... won't go into that just now.