I regularly find Slack annoying.
Nothing is more distracting than its notification blips, drops, clicks and beeps in a closed office space. I’m trying to concentrate here, dammit!
Here is a trick-and-a-half that I use to make my life easier.
Turn on System-level DND
I use Windows for work/play. I recently discovered the beauty of an OS-level “Do Not Disturb” toggle.
I forgot to turn it off one day, and I had one of the most productive days in recent memory the following day.
MacOS should have a similar system. Linux….I’m not so sure.
I flip the switch whenever I need to get sh*t done. Granted, it’ll mute everything- including you team, the bots, the notifications about Travis CI on the #product-develop channel, and your boss, but you are much more likely to reach productivity zen. Your call!
Use the “Add reaction …” for acknowledging stuff
In my experience, a fair amount of Slack messages are of the form:
Hey, I just sent you that super important document, can you review it?
or
Is it alright if I update Gitlab now?
or
$person_A is on leave today, please redirect all merge requests to me
Notice how, in a well-functioning team, the reply to all of these are affirmative.
This is an opportunity to do your team mate a service- just let him/her know that you have seen their message and reply with a 
or a 
Since Slack doesn’t send a notification for reactions, you have successfully acknowledged their message without a blip, drop, click or beep.
Epilogue
16th October, 2018: Messenger has replaced Slack as the chief productivity killer in my life. Except it’s much worst.