For me personally, the hard thing is reading the thoughts of Plato, Seneca, Marcus Aurelius, etc. and then trying to understand how we had such amazing thinkers 2000 years ago and that we don't seem to have moved any further at all in the year 2018. Yes, of course science and technology have progressed, but our human behaviors have not improved. In fact, we seem to have regressed and now have Donald Trump as President and Theresa May in the UK, trying to pull the country out of Europe due to rampant xenophobia.
Anti-intellectualism, anti-science, anti-vaxx, climate change denial, rampant capitalism at the expense of our souls. It seems like the default goal of the Westerner is to get rich enough so that they can narcotize themselves against all the pain and fear of the future which is underlying our society.
Southern California, where I live, is a place where your instagram "image" seems more important than whether you're actually a good person. People spend more of their time glued to their screens scrolling on Insta or Facebook seeing other people's portrayed lives and obsessing over their likes and follows. Working long days so you can afford the next step up on the car ladder or housing ladder, so you can get some temporary satisfaction before that fades and you start the ladder again.
I think if Socrates or Plato or Aristotle were to time travel to this future, Socrates would be sharing his hemlock with them before they committed group suicide.