The danger of conference calls
Once my boss got a call from a vice president of something-or-another, put the call on speakerphone and called me to listen to the conversation as it would deal with a project I was working on.
When I was getting there my boss was telling his counterpart 'glad it's just you and not idiot [redacted name] or we'd be here all night explaining stuff'
To which [redacted name] replied, in a somewhat gloomy tone, 'hey man, that's not funny'
That day I learnt to always ask who's on the other side of calls before calling any names :)