Tools can't reliably fetch sandwiches:

'My usual.' or 'ham salad, easy on the mayo.'

Then the robot has to cross the street, queue at the sandwich store, discover that they're fresh out of mayo, or whatever, and has to decide what to do next. Should it contact you for new instructions, take the initiative and visit a different place, buy ingredients and prepare a snack personally, or any other of countless possibilities? Any of which may involve handling new, unanticipated phenomena.

Thus fetching a sandwich, reliably, is a creative task, and any entity capable of doing it has achieved human status.