My favourite Slack anti-pattern:

Person: Hey, do you have a minute for a quick call?
Me: Sure!
[15 minutes goes by]
Me: Okay, well, I need to go do something else now, but I’ll be available in 20 minutes.
Person: [attempts to call immediately]
[20 minutes goes by]
Me: Alright, I’m free again.
[10 minutes goes by]
Person: Too late, I’m busy.
Me: 😑😐😡