I treat CHAT this way. If I am in the zone and focused I’ll invariably be ambushed by a chat message that will take my productivity hostage because THAT person needs something that ‘could’ have been emailed, but instead they elected to send it via chat. Thus needing immediate action. Then it takes me a few minutes to get back where I left off and get back into my zone.
The emails I hate are from people who don’t give me all of the information I need and spread it over 9 or 10 little emails that could have been consolidated into a couple. Or when I’ve assigned a time I need something by and they send it well after-the-fact as though my cut off was just a suggestion instead of realizing that I have other things to do.