What will be the "turns out cigarettes are bad for us" of this generation?

Alcohol. The parallels with cigarette advertising is shocking. Does depend on what generation you're referring to though.

Internet Porn.

DavyD_83 wrote: »

And earphones, it can't possibly be good for us to have a constant stream of audio pretty much all the time.

you're not married then?

Global warming possibly. We're not doing that much to combat it. Millions may die from it. Loads of species will become extinct. Future generation may well look back at this precise period of time and wonder why little was done about it when we have a hell of a lot of facts about it.

Grayson wrote: »

Global warming possibly. We're not doing that much to combat it. Millions may die from it. Loads of species will become extinct. Future generation may well look back at this precise period of time and wonder why little was done about it when we have a hell of a lot of facts about it.

Possibly?

Hate to break it to you buddy but we're long past the point of no return with climate change. It's coming, and it's going to bugger everything up, probably in our children's lifetimes.

If people think the "mass" immigration into Europe right now is bad...

Internet, Facebook, Google. Newsfeeds and "stories", etc.
Not sure though if it's this generation or much later in the future.

Processed foods, eating plastics due to fish eating plastic and we eating said fish, pesticides and other stuff that is sprayed on plant food that is directly eaten.

In terms of people looking back and thinking, "what were they thinking?!", I reckon there is one near term obvious one and one further out. Near term, I think internal combustion engines are the biggest one. We effectively walk around in a stew of pollution emitted by burning petrol in a device whose basic design hasn't changed much in a 100 years. The consequences to the generation who grew up in "peak ICE" era will be devastating.

The less obvious one I think is racing animals (horse racing/greyhound racing). If you look at it as though it had never been a thing, the idea that we would get sport out of rearing and training animals to carry us round a track in a race is... barbaric? A coming generation will be as appalled as we are now when we look back at animal circuses or, going further back, bear baiting as entertainment.