Alcohol.
Lots and lots of people lean heavily on it and think that alcohol is the spice of their life. When, it contributes to so many problems than it’s so-called benefits. We tried, in America anyways, to outright ban alcohol. Problem was that the person who wanted it banned, was too extremist.
Like he didn’t think it all through and think just going for the jugular of the problem is what will work. When, it didn’t and just made people work around it until eventually the ban was dismantled.
So, since then, we’ve been putting up with drunk drivers, drunk disputes, drunk abusers and other issues. I still wish we could just slam our hands down at the desk and demand we sit to discuss in how to properly deal with this issue than people proclaiming that it’s not a problem.
alcohol is especially hard to ban because it’s just sugar and yeast, and you can even use natural yeast if it gets banned, and you can use fruit if sugar gets banned. While with drugs some tyrannical empire might be able to ban every single lab-related equipment and chemical (and even then, you would be surprised what people can make by themselves without anything else other then natural resources, I mean that’s how we got here as a species), alcohol is such a simple recipe that it’s just plain impossible to regulate effectively, and the current way of having it cheap enough that people don’t brew their own but expensive enough that the 99% of the population doesn’t turn into alcoholics is good enough