(Post-communist country, so this might be specific)
-The overall quality of air (the ''cleanliness'' of diesel engines in trucks and heavy machinery has significantly improved in last 30 years),
-The omnipresent cigarette smoke (There used to be almost nowhere to sit inside and have something to eat or drink without being soaked in the smoke after a while, you had to have separate sets of clothes for that. Every time someone brings up the good old times when it was allowed to smoke in public interiors because the modern alternatives ''aren't quite it'', I wish for Total Smoker Death again.)
-Dog shit absolutely everywhere. Almost everyone had a dog, or it seemed like that, and training them wasn't really a thing and picking up their shit neither. I still refuse to walk on city grass, let alone sit on it. When you live your entire childhood with the fact that your every first step from the house might be right into a shit, every getting off a car into shit again and every literal touching the grass results in being covered in shit, you have to be aware about every step you take. (at least this wasn't Yugoslavia, cos I'd have to worry about landmines too)
These years, dog owners are mostly disciplined by bans and fines.
-Pre-internet lack of possibilities to share experience with other people, be it professional or personal ones. Reddit and such might be far from ideal, but still better than feeling alone and isolated with own problems.