It's when that "Somebody" crashes their car or bike or motorcycle or RV into you as you were carefully following all traffic rules that a helmet would be appreciated.

I have no control over the other yahoos out on the road nor can always be on the lookout for deer or dogs while riding. Sometimes bad ***** just happens so taking a small precaution by wearing a helmet makes good sense.

A helmet is cheap insurance. Do you understand insurance? Do you not carry it for yourself, your spouse, your house, your car? If so, why? After all, "Nearly all of these crashes or collisions have a primal cause where somebody (or somebodies) got careless, or was negligent, or otherwise screwed up."