The only real point is the 3rd. I agree the 'Hi' type are annoying, but I for sure don't expect a stack trace. Worst case the person is from another team, and

The only real point is the 3rd. I agree the 'Hi' type are annoying, but I for sure don't expect a stack trace. Worst case the person is from another team, and I would rather have context on why they're contacting me directly on IM. Best case is that's a coworker, and I trust that if my coworkers ask me in particular and not my team's chat, its a specific issue I will have an easier time dealing with (or I made myself available for help because I'm on toilet duty and will jump for anything remotely interesting). If I am engaged with you and you ask me for a quick call, I either have 30 minutes ahead and agree, or I don't, and refuse. I fully expect the call to last anywhere between 2 and 30 minutes (unless you're a PO and I set aside 2 hours). The more we understand each other, the quicker the calls will be anyway, so even if the call isn't 'productive', it ultimately is.