@Fragglemuppet For me it was a case of several months of Twitter (which I used exclusively through the web interface on
twitter.com itself) slowly becoming increasingly difficult to use.
First I would occasionally notice that the setting to have posts appear in chronological order had mysteriously toggled itself off, and I wasn't seeing the tweets I was looking for at the top of the timeline. Then it would start to happen more frequently. Eventually it got to the point where I would wake up, log into Twitter, the timeline was non-chronological even though I had toggled the chronological setting to on, and I would have to refresh the page to try to make it take effect. Some days I would open Twitter and refresh 10, 20, 30 times before the timeline looked like it had the tweets in order.
At the same time as this, I would also notice that sometimes tweets from certain people would just not appear in my feed at all.
Then Twitter would start hitting me with a modal dialog telling me that my browser was outdated, and recommending me to switch to Microsoft Edge or something like that, which was both wrong (I was using the latest Firefox) and highly insulting.
Around this time is also when they started injecting random notifications into the timeline. So I would see messages to the tune of "person X liked this tweet by person Y" followed by the body of the tweet from person Y, and I would have no idea who person Y was, and sometimes I would very much not want to see the things that person Y was tweeting. But I couldn't find any way to remedy this.
So that was when it got to a tipping point for me, and between not being able to see tweets from the people I was trying to talk to, and seeing lots of tweets from people I did not want to see tweets from, Twitter was simply unusable for me, and in the span of about a day and a half I decided that I would simply have to leave and make do with something else.
At least here on the fediverse I know that no matter what problems I encounter, it won't be those specific ones. Because if nothing else, I can choose what software I run on my instance, and what client I use to access it.