It seems like it's been super popular to call each year that passes the worst, but 2020 is the first year (in America) that really warranted such a title. We have a vaccine now that is presumably safe and effective, as well as a new president who almost certainly by default will be better than the last one. Barring a new 2021 pandemic that kills another 2m people and destroys countless other lives and businesses, it's pretty easy to guess that 2021 will be an improvement.
As an aside, I would also like to mention that 2020 gave us the BLM protests. I don't think I can properly articulate all the emotions I felt seeing BLM explode like that, or the significance I hope this year plays in the history of America. I will simply say that I have been incredibly proud and humbled by the protesters, and I think 2020 is the year a lot of people woke up to how things really are in this country.