Agree with this. Perhaps it's my British sensibilities, but I find it rude when people launch straight in.
Niceites are, well, nice. They help to make sure everyone remembers we’re all human beings rather than question answering machines, but we are also talking to get a job done. Unless you’re actually a good friend of mine if you drop me a message asking me how my weekend was, I know that you’re just lining up to ask me a question, but now I have to do The Dance to work out what it’s going to be about, whether I have time for it, and if I’m even the right person to ask.
> Them: "Hi"
> ...
> Me: "What's up"
> ...
> Them: "Do you have 5 minutes to join this conversation?"
> ...
is awful.