> Anyway, the real problem is people who ask “what were you typing?” when you delete your message. That seems so rude to me!

I've never actually had this happen to me, but I nonetheless fear it will 100% of the time I start typing something and then delete it. In any IM application that has a typing indicator (especially Slack at work -- I shudder at the thought of typing out a long message in #general), I've taken to drafting messages that require any non-trivial degree of thought to type in a separate box, e.g. a message to myself, and then copy-pasting it into the actual chat.