Dear Carolyn: Before my older brother was born, my grandfather died of lung disease because of smoking. At that time, my mom decided to quit smoking.

Two or three years ago, she and my dad both started to smoke for social reasons. They don't smoke around me, but I find cigarettes in their cars and I smell smoke on them, and sometimes they disappear for a few minutes. They sneak around me because they know how I feel about their habit, and they lie on occasion when I find evidence. I have made bargains (always broken), I have cajoled and pleaded, I have tried being tough, and I have tried tiptoeing around them. Nothing seems to work.

How can I get them to start thinking about quitting? I don't want to nag, but it tears me up inside when I think that maybe my future children will never get to meet them, just like I never got to meet my grandpa. I can't just stand by and do nothing while they slowly kill themselves.

-- Maryland

Dear Maryland: Why not? Your parents are two adults with a perfectly legal habit.

A perfectly stupid one, sure. It is, however, their stupid decision to make, and so any child who "can't" let them live their own lives needs to learn his or her place.

I am siding with the smokers! Not what you hoped for, I'd venture. However, assuming full responsibility for other people's decisions will make for a frustrating slog through life -- and that's the unspoken motivation driving anyone who "can't just stand by." You can't do it ... without blaming yourself for not stopping them. Right?

The problem is, the assumptions feeding that guilt -- that you actually can, and actually should, stop them -- are false. Your bargaining, cajoling, pleading, confronting and tiptoeing, and their lying, sneaking and continued smoking, all have tried with all their might to get that through your head.

It's a deflating message; I can see why you're loath to receive it.

However, embracing your irrelevance isn't the only option, nor is, "Go ahead, die, see if I care," the only thing left to say. Loving engagement with others can have an uplifting effect.

The operative word being "can." Not "will." So: You do your part, by making your point until you have some clear sign they know how you feel -- such as, their lying and hiding from you -- and then you let them do their part, which is to heed or ignore what they choose.

Dear Carolyn: How much truth is there to the "If he hasn't married you by now, he never will" scenario? It has been over four years, and we are both over 30.

-- D.C.

Dear D.C.: I don't know, because I don't know either of you, and the only quantity of truth that matters is your own.

But I do know that you will know exactly how much truth you're staring at when you (1) remind yourself that you're not an adolescent, you're an adult, and therefore can (2) admit to yourself everything you already know but would rather not; and (3) gather up whatever questions, and whatever (spine), you have left, and ask him yourself. Including "Will you marry me?" if that's still what you want to know.