Taking an international flight where half the plane is smoking. Those were good times, especially in Greece where they loved smoking even more than the Americans.
I read a lot of Southeast Asian countries still smoke everywhere. And I can't imagine being cramped in a small area with a nasty ass smoker without flipping out.
Actually, air was cleaner back when smoking was allowed on flights. They had to completely recycle all the air in the cabin where nowadays it's all a closed system. Every fart and cough, every armpit outgassing and nasty crotch reek is with you from takeoff to touchdown now.
Most of you won't believe me so I suggest you look it up yourself before downvoting (which you won't).