People have been saying "this year sucks" for a number of years. It's been a recurring meme. And obviously 2020 was rougher for more people than most years are.
But why aren't people more comfortable saying, "things are going pretty well for me"?
I think the obvious answer is that it can sound a tad insensitive to people experiencing hardship. Say what you will of the internet, but it has a way of giving people hard on their luck plenty of airtime (now, if you're actually deeply impoverished, probably not – the global poor are not particularly visible to the West). So we've all responded by becoming a tad more sensitive to celebrating during someone else's hardship.
But here's the thing: it's always someone's hardship, on a vast enough internet, with enough distance acquaintances to worry about. I'm not sure you would ever be comfortable enough to ask a friend to cancel a birthday party because your uncle died, even if they were a relatively close friend. So I think this social response is out of proportion. Pandering to the "things suck" narrative is far too easy, and seems inescapable.
And we should be more open to the idea that people, even when they're not doing well, might be legitimately happy for us. That they can celebrate our success even if they're not doing as well. I think that's an essential element of being friends, so I feel it's okay to just ignore people that aren't like that. If you want to build a social norm where success isn't celebrated (in the most general sense – the achieving of goals, building and using moral character, etc.), then we simply are not engaged in the same civic project. I feel like I've been saying and thinking that more and more, but perhaps that's because I've been getting more and more specific about precisely what civic project I'm trying to engage in.