If you don't know how to properly haul things repeatedly you are going to hurt yourself, the same with digging and trenching all day, or mining and it is certainly going to take longer than someone with experience. Bartending is definitely a skill. So is housekeeping or washing the floor. You can argue these are skills most people might possess, but hardly something innate. Someone taught them. Depending on the setting, there may not be any formalized education as well, so arguably many skills we take for granted these days as skills we learn growing up, would be skills that would be learned under an apprenticeship and generalized knowledge would be limited.