I'm peronally pretty skeptical about second hand smoking being a major health issue. Smokers generally try not to blow their smoke in people's face and far from children (at least I do), and even tho you'd inhale less thant 1/10 or 1/20 of the quantity of smoke a regular smoker does.
I understand the smell being repellant for non-smoking people tho.

But I think there are way worst substances we inhale everyday in our current atmosphere : car gaz, industrial rejections, chemical products etc... hell even barbecue causes cancer.
I'm not saying second-hand smoke is only bullshit, I'm saying I don't think it's the only cause of "breath" related cancers for non-smoking people.

I smoke reasonnably, I'm not one of those smoking a pack of cigarets daily. I think it's like any other substance, it's all about control and not smoking in excess. Humans have been doing drugs since the dawn of time afterall, it's his industrialisation that allows us to use more than reason allows.

And to asnwer your question : do you think smoking is worth a shorter life and possibly endangering the lives around you?

I personally think that smoking or not, we'll most likely get some cancer from something else considering our actual way of consuming industrial shitty stuff. And life can be shortened by so many things... accidents, unexpected diseases, bad choices, cataclisms, and in some countries : wars and bombings etc...
So I think smoking is a lesser problem for me, as long as it stays reasonnable and still allows me to do some sports without breathing issues, and if it does someday I'd probably cut back a lot. But then again, it's only my opinion.