How about...(From someone who was 17 then...)
Air and water are cleaner in most places in America now than they were in 1900.
Deer, coyotes, and mountain lions are a growing urban problem.
Oh, and about that fish problem...Aside from Minamata Bay, not a single clinical case of mercury poisoning associated with fish consumption is to be found in the scientific literature.
We have six billion people today, not eight, and the population explosion is now a bust, mostly without mandatory birth control. Well-fed, developed nations have a significantly lower birth rate than those that are still "natural".
India is self-supporting, and considered a center of music, movies, and computer software.
Africa is still a mess, but more due to political chaos than lack of land, water, or sunshine.
Marxism didn't work. Period. And most of the formerly Communist countries gave it up.
Vietnam vets now have more respect than the protestors do.
The secret network of mainframes maintained by the Department of Defense is now used by millions of people to play games, chat, and buy things, and is considered old hat as news.
Having sex can cause cancer, rather than the lack of it.
Steak is unhealthy. Potatoes are good for you.
By the way, there is no such thing as a "healthy tan".
The data of the CIA is being warehoused by a private company founded and run by a flamboyant playboy who makes no secret of it. And no, he's not an old-money WASP, but an orphan. You'd love his mansion...designed by a Buddhist priest.
The NSA runs a puzzle page for children, and an annual contest where they dare people to crack their codes. Most of the prize money is given to charity.
The two most-trusted women in America are a black single woman and an open lesbian.
You can see any movie older than 18 months ago with a cheap viewer that fits on your TV. People collect movies like books.
The recording industry is being bypassed by individual artists posting their music for free. Radio airplay is becoming irrelevant as a measure of success.
Most people define themselves by their work, and a good job is one where you don't wear a suit. Engineering is higher status than Personnel, and being an entrepreneur or in a small company carries more status than joining a large one.
A man with noticeable stubble was on the cover of Fortune, a business tycoon was pictured on the cover of Time barefoot, and neither of these were mistakes.
It's a compliment to call a rock singer a good businessman.
The most abiding legacy of Abbie Hoffman was his efforts in telephony.
Blacks are now 80% middle class, but they cling to their image as poor, illiterate, and criminal as a matter of racial pride.
Cocaine is considered worse than heroin, more addictive, and is a problem among the poor -- few wealthy or famous people admit to ever having taken it.
LSD is boring.
Most American housewives work, and very few of them ever worry about food prices.
Children make play dates, and few of them simply "go outside" to play.
Girls are encouraged to participate in sports, are more likely to go on to college than boys, and are assessed by earning potential as much as domestic skills by potential mates.
It's not unusual to sleep on the floor, the way Japanese do, and most Americans can use chopsticks.
In general, life in 1975 was far more pessimistic than it is now. Environmentalists were predicting major problems for America in the next 25 years, ranging from food shortages to literally unbreathable air. The energy crisis suggested that oil and gas were being exhausted -- technological optimism peaked about the time of the Moon Landing. That, and the "Victory Gardens" planted by many people made it seemed as if we were about to return to agrarianism, soon after a Marxist-style revolution seized power, returning us to a pristine state of neo-tribalism, or at the most, an America of pioneer and Colonial era-level small towns. Economically, we were locked into a "stagflation" that seemed to have no end in sight, and the prevailing wisdom held that women in the workforce would only make things worse. Perhaps the most shocking statement I could send back is:
Everything you worry about will be many times better, but people will continue to feel just as bad.