Oh I agree. But it could be a sticky situation for a spouse, depending where you are, and what your mental capacity is. Around here, many hospitals will ignore a DNR. Days before a surgery,the surgeon told me that the hospital it would occur in would ignore my DNR as the hospital is a religious-affiliated institution. And that's not the first time I've heard that.
Outside of the health care environment, if one suddenly suffers cardiac arrest, and a loved one is there and knows your wishes, it may take a while to get emergency attention... particularly if said loved one panics and doesn't know what to do... or say didn't notice that the person hadn't moved for a while...
There are people to who something like this is so abhorrent, they think they control your life, and they will not let you decide. They are "doing it in your best interest" whether you like it or not. Which leads people to either suffer on and on miserably, or to take the messy Hemingway Exit while they still can. I'm a "hands off me!" person. I think it is an inalienable right for me to decide if, when, and where. I cannot think of anything more independent than that, and we are a nation founded on "independence". I wish society in this country would appreciate that, and just butt out!