Chat history
Every time I open Facebook Messenger, I wish all chat platforms defaulted to deleting the messages after some period of time.
I don't know about you, but I hate it when I open a chat with a friend I don't talk to as much anymore, and the last message from two years ago is something that didn't age well, for one reason or another.
I like how Signal does it. You can have the history forever, but I set it for four weeks in all my chats. I don't remember what I talked about with my friends after a month, why should it be different for text chats?
When I've discussed this topic with people around me, they don't like it: "But what you need to look up what the other person said later?" Well, how do you do it when you have a conversation in person? You either write it down, or you ask them to refresh your memory. I do that with people on Signal, and it isn't weird or annoying.
Of course this wouldn't work well for work-related things, or for community projects that rely on searchable chat history, but that's not what I'm concerned about here.