People have, and always have had, all kinds of superstitions. Here, however, I'm not talking about superstitions like "the number 13 is unlucky" or "walking under a ladder is bad luck". Rather, I'm talking about the worship and idolization of the past, so to speak.
This takes several forms. One of the most common ones is the notion that life was somehow better in the past. Somehow people seem to think of the past as an utopia, where people were one with nature, stress free, frolicking among flowers on the meadow, rural landscapes with carefree farmers cultivating fields at their leisure, windmills producing flour from their grains, and bakers making bread, and everything being sunny and shiny, and people being happy and nice. This is contrasted with a picture of the modern world with people making long hours in dark factories and office buildings, always being busy and stressed, always having to hurry everywhere, with crime and violence rampant, in a dark city full of pollution, noise and danger, economic crises, corruption and evil everywhere. They seem to think that crime and unhappiness are today at an all-time high, while in the idyllic past they were in an all-time low, with people being happy and carefree.
The above paragraph might have contained a slight amount of exaggeration, but it's not far from the picture that many people have about the past (and present).
Reality, however, was quite different from that imagined utopia. That's not to say that no single human being ever existed in the past that lived in a place that could somewhat resemble that picture, but not only was that a really small minority of people, even their lives were not that rose-colored.
For the vast majority of the history of humanity people (with the exception of a very small minority) have lived in rather horrible conditions. Infant mortality was very high (in many cases, at many places, you were lucky if half of your children lived to adulthood, which is one of the reasons why people got a lot more children in the past than today), life expectancy was quite low, and diseases were rampant (many of them being diseases that are trivially curable or treatable today). Modern medicine has made most of those diseases insignificant, and has diminished infant mortality to almost zero, and raised life expectancy significantly.
If you think that today the gap between the rich and the poor is wide, you have no idea how it was in the past. Today, in most countries, even poor people live relatively comfortably. In the past, however, in most places poor people lived in absolutely horrendous conditions. In most countries neither the rich nor the government cared much about the poor, or even the middle class, and there wasn't much of things like sanitation and public infrastructure. Many poor people lived, essentially, in a mud hut. And, naturally, crime was rampant, so life was really unsafe.
And those happy farmers? Some thrived, others didn't. Without modern technology they were much more susceptible to bad weather conditions. And usually they were helpless against roaming bandits and, often, to corrupt officials. Some small isolated communities were probably better off than larger ones. But of course even there the problems with high infant mortality, diseases and low life expectancy were ever present.
Some people often picture the middle ages as a likewise idyllic time, where knights in white armor saved princesses (or, perhaps more realistically, helped those in need). This picture might not be today as prevalent as it was decades ago thanks to movies today often depicting the middle ages more realistically. It was much darker and grittier than that. And those knights were often, effectively, just soldiers of the government, and many of them didn't have codes of honor (or didn't follow them). Pillaging and raping was not always done solely by bandits.
The modern world, however, is much safer in comparison. Of course crime is still prevalent (and will probably always be), but the modern world is more peaceful than the world has ever been. This might be hard for many people to believe, but it just is. There is less war, less crime and less corruption overall today than there has ever been in the past. That might be hard to believe seeing how much of it there still is, but that only emphasizes how bad things were in the past.
Another, perhaps less prevalent, form of idolizing the past is the notion that ancient cultures often had knowledge (usually related to medical treatments and medicine) that has been lost. Often miracle cures are sold as being ancient knowledge, that wise people in the distant past had but which has been lost, and recently rediscovered. Miracle cancer cures are perhaps the most prevalent form or this.
This kind of mentality is very often accompanied with the very strange notion that modern medicine is little more than voodoo and quackery, where greedy pharmaceutical corporations are both shooting in the dark with wild experiments using people as their subjects, and making a big profit out of it. In other words, they are more interested in making money than curing people, and medicine in general is more like a mad science experiment. Of course ancient people were "one with nature", and very wise, and had all kinds of natural remedies that were effectively panaceas, and which have been either forgotten or suppressed by modern greedy pharmaceutical companies.
In fact, and of course, the vast majority of those "ancient miracle cures" are pure fabrications. In an extremely small amount of cases there might be some truth behind the claim, but even then the actual remedy wasn't really all that effective, and is very well known and accepted today (but, often, there are much more effective alternatives to it using modern medicine).
The fact is that modern medicine puts all "ancient cures" to shame in its efficacy and safety. Modern medicine has eradicated some diseases completely, and has made many diseases trivially curable and treatable, those diseases going from almost certainly fatal to not fatal at all.