Actually, a lot of the diseases that we now have to protect ourselves from since the agricultural era was due to the agricultural era. While disease and infection and impacted many pre-agricultural communities, they weren't dying off as much as a lot of people like to think they were. Again, a lot of diseases came from permanent human settlements, where a large number of humans were living close to one another and with animals. Along with that, comfort is relative. Someone raised in a hunter-gatherer society may prefer that lifestyle over being forced into living a more modern-day lifestyle. While you would have had to deal with things, like the elements, you also would have had way more leisurely time and a much closer community to lay back on. Modern humans work longer hours to survive and a lot of people are dealing with issues revolving around loneliness right now.
Along with that, while modern medicine is great, the way it's being used for profit in some parts of the world isn't. Modern medicine isn't accessible to many of those who are poor and living in developing countries. Drug laws are also not based on safety, which is why you have cases of drugs, like many classic psychedelics and cannabis, being illegal in many parts of the world while more dangerous drugs are more readily available. You also have the many cases of big pharma knowingly pushing drugs that are addictive and harmful to maximize their profits.
You also have issues with racism, which wouldn't have been as prominent in the past due to race not even being a thing throughout most of human history. The patriarchal structure that we see today didn't start until around the agricultural era either. Queerphobia likely wasn't as big of a thing back then (pre-agriculture) in comparison to now. We are having issues with how screen time is impacting the brains of children and children and now being exposed to more and more disturbing content through online spaces. We can go on and on about the problems of modern day society and why it, as a whole, isn't any better than any other time.
It's important to remember that everyone things that they grew up in the best time period. At the end of the day, which time period is the best is completely subjective. Every time period has its good side and bad side and we shouldn't treat the different parts of human history as just good or bad.