What if when you couldn't feel pain, you also couldn't get injured?
On the up side:
- If your bare feet were numb from being outside in frozen weather, you might not notice if you were lacerating them on frozen icicles. But now it doesn't matter, because the icicles can't hurt you.
- You could dunk your hands in a numbing solution and then punch whatever (or whomever!) you liked with no broken bones.
On the down-side:
- Surgery would be pretty painful, because once anesthetized, a surgeon's knife couldn't cut you. You'd have no choice but to get cut open with no drugs (ouch!)
Would it be worth the tradeoff for you?