To bombman,
I see you’ve been too long in Yeshiva. The reason that smoking can possibly be compared to crossing the street (even though I think you can’t compare it anymore -see previous post.) and not to jumping off buildings is because the purposes are different.
When you jump off a building -the main purpose is to hurt yourself (even if you think you can fly) -this is the basic purpose of your actions. When you cross a street- it’s to get to the other side. When you smoke it’s to enjoy the smoke. The Torah would never matter an action whose main purpose (eg. jumping from some high place) is to hurt yourself since you can use the stairs or elevator. In other words, normal people don’t jump off buidings just because they need to get to the ground floor!