Pain is a great teacher.

If you had the hardware to build a robot that could “feel” the world around it, and you wanted it to self-teach how to move around on its own (so that you don’t have to pre-define movement paths), you would probably program in a system that could interpret potentially damaging sensations as danger/bad and avoid them automatically (too hot/too cold/too sharp/too hard/etc). That system would essentially be a pain response.