The mid 20th century in the United States seems to really stand out as a period of time where popular sentiment was overwhelmingly optimistic about the future - space travel, the possibility of flying cars, jet packs, etc. Were sentiments really that hopeful in actuality?
On top of that, how does that kind of optimism for the future compare with other eras of history? Today it seems like there's much less optimism for the future, between global warming and conflict in the Middle East and such. There's a lot of belief in past eras being the 'golden years' or 'golden generations,' a belief that dates back (IIRC) to Roman and Greek schools of thought - I know Ovid in Metamorphoses talks a lot about his contemporary era was an 'iron' era in comparison the 'golden,' 'silver,' and 'bronze' eras that preceded it.
The early 20th century had a similar burst of optimism. Science and industry made tremendous advances. Cars! Airplanes! Electric light! The world had been mostly explored and man was its master. New theories about human nature covering everything from management to psychology to politics gained strength and promised a great future of progress.
Then WW1 gave everyone a big reality check.
Well, it didn't last long, but the fall of Communism in Hungary was followed by euphoria and for the first 2-3 years people were extremely optimistic about how we would reach the Western Europen standard of living within a few years. People were enthusiastic about starting businesses (which they were not allowed before) and the society was overall very optimistic about the future. Unfortunately it soon turned out that the transition will be a much longer and more painful process.