I worked as a sys admin at an online brokerage for several years. Our team was spread out all over the country, so every morning we'd have a 30 minute pre-market conference call to talk anything that could affect trading like internal issues or outside stuff like earnings reports or fed news that could lead to high market activity.
Our director was a Dwight Shrute type turd who felt like he wasn't doing his job if he wasn't regularly raking his people over the coals, so every single morning it was guaranteed that one or more of us was going to get singled out in this meeting for a trip through the shredder in front of all his/her coworkers. It was fucking brutal and was easily the worst part of the day. My routine for joining this call was ingrained: Dial in, enter passcode, and mute my mic.
The other sys admin and I shared an office. He sat on the opposite side of the room facing the wall. A good 10 feet away. One particularly stressful morning as everyone is joining the call, I say to my office mate something along the lines of, "I wonder who fuckhead is gonna put on the rack today." I immediately hear Dwight reply, "This morning I think we'll start with you, TS." Turns out my office mate wasn't a stickler for mute discipline like I was. That was the beginning of the end of my tenure at that company.
Tl;dr A hot mic picked me up talking honest and unfiltered shit about my boss during a conference call.