Staring from the point you've suggested, I would say:

People don't think pain is bad -- not when it directs them to do something in their interest like let go of a hot stove, or be aware they have a broken bone. Moreover, on careful reflection, most people would want to get a pain signal when e.g. cancer is developing so they can treat it at the earliest possible time, and will be shielded from any procrastination.