2. Cookie banners everywhere. A standard protocol needs to be created.
3. Software subscriptions without a one time payment option.
4. Electron apps because building using native toolkits is to time consuming.
CNN also does this with video reports. If you want to rewind to hear the end of the video -- you can't, because you're now instead watching an entirely different video.
For instance, so many wikis remove things like category boxes and navigation bars on mobile, making it a chore to browse different related articles. They also seem to like hiding stuff like 'recent changes' too, as if knowing what changed since your last visit is something only desktop users have the need for.
And god help you if you want to actually contribute to many sites on mobile. That seems to be a complete afterthought for anything without a mobile app (and arguably a lot of those that do have one).
Not having a central place where the administrator can verify what the system thinks is the system time.
Reducing feature set when rolling out new backend that I didn't ask for.
I never really liked it due to the 250 character limit (used to be 150) and people insisting that it is possible to have a meaningful discussion within this limitation. Sure, you can split your post into multiple messages but the design of the site encourages short responses so no real discussion will be happening.
The shortness of messages was also a perfect fit for what early users of Twitter were doing: answering the question of "What are you doing?"
There was a trend when Twitter began of adjusting your AIM "status" message to reflect what you were doing, or what music you were listening too (there were scripts that automated this for you).
As an early adopter of Twitter, I can recall that people started using it in similar ways. One of the first Twitter messages that I received in the early days was from @ev saying "Peeing."
I think it's fair to say things haven't changed much.
And there's one site where when I pull up a new web page and try to scroll down to read the first line of its article -- I can't, because focus for some reason is on their sidebar.