This is going to change really soon, with the advent of legalization.
I live in Japan right now and you can smoke tobacco practically anywhere. Cafe's, bars, etc.
Actually, when I was in high school here 10 years ago you could even smoke on school property - as in, I had a teacher who used to smoke in the classroom.
It's a shock for me when I go back to Canada sometimes and light a cigarette outside a club or something and have a complete stranger walk past me and boldly look me dead in the eye and go,
"that's fucking disgusting, bro."
or have people do the Zoolander I've-got-the-black-lung fake cough if I light up a smoke and they're standing nearby.
In the past 10 years the anti-smoking propaganda in North America got really intense (to the point of calling complete strangers "disgusting", or sneering at people who smoke) people have stopped smoking. Of course, this is in addition to other things.
It's because smoking is considered "gross" now.
If you look at Holland's rate of MJ usage, it's like 40% less than what Americans do, per-capita.
The reason for this is that when MJ use is normalized and you can smoke it in public, you make a transition from mores to folkways. That means, that rather than having actual laws against smoking weed, people who disagree with it resort to lecturing, giving rude looks or negative body language.
Let me paint a picture for you -
Imagine it's 15 years down the road and weed is completely legal, absolutely everywhere. It's not even a question anymore.
You're at a work party and you pull out a joint and ask your colleges who wants to step out for a puff and they all sort of just give you a look and go "uh, sorry. don't smoke".
Then you go out and have the puff yourself, and when you come back in everyone's now looking at you like "oh, there's that guy who's high."
Trust me - as the legalization movement moves forward, the overall rate of people smoking is going to go down by a lot, just based on the transition of it being "cool" or "rebellious" to being something that "those people do."