The first time I ever flew as a kid, I was so excited to be on a plane! And then it turned out to be a 5 hour+ flight with negligible entertainment options and I was so bored...

And then, another dude got bored so he moved to the empty back rows of the plane and smoked for the rest of the flight, and the whole plane was suffused with the smell, and I was so sick.

Like, even those who smoke generally hate the smell of that stale second-hand smoke, especially if locked up in an enclosed space for hours.