Favourite pet peeve: People who mention me or DM me to get my attention, and then patiently waits for a response before asking the non-critical question they could just have typed out and left for me to deal with when I have time. That kind of behaviour seems to be considered acceptable on realtime environments, and it's 10 times more disruptive than sending an e-mail..

slack is not disrupting my attention a lot because I have subscribed only to direct messages and bugs assigned to me directly by QA. I make sure I reduce subscriptions as much as possible by muting most of the channels.

Yeah, that's how it should be. But I'm sure for many it's not.