Thing Not To Do Today: have the vapours.

 Robert Cruikshank: A dandy fainting, or, An exquisite in fits: scene a private box opera. 1835

I wouldn't recommend having the vapours, but I can't deny it's more a lot more fun than it used to be.

Nowadays having the vapours might involve a little light shrieking caused by (for instance) finding a frog in your lettuce. Or it might consist of a bit of gasping and having-to-sit-down after some less violent shock, such as winning the lottery or bumping into George Clooney.

Nowadays, having the vapours usually implies making a fuss over not-very-much. It's generally an excuse for the sufferer to take centre stage; observers (and there are always observers) will probably be cynical, even if they're outwardly sympathetic.

Long ago, though, (even before the Cruikshank cartoon above) having the vapours was no fun at all. It meant being depressed, and was believed to be caused by vaporous exhalations from the stomach. 

Hmm...

...well, I suppose having that much gas would get anyone down, wouldn't it.

Thing Not To Do Today: have the vapours. This Latin word came into English in the 1300s. The Latin form is vapor, which spelling is used in the USA today.