For me, keeping cool in these situations means being assertive yet kind, no matter how tough it gets. It's definitely easier said than done :))
Back in my days as a CSM at a SaaS company, I bumped into my fair share of not-so-happy campers :D Some even got a bit colorful with their language. For me, the trick is not to take it personally. Instead, I'd politely let 'em know that if they kept at...