Nobody likes to be called a liar. It’s one of the most salient insults we have as a culture, and it can be bandied around at any time. It hurts to hear almost more than anything else. Because if you’re a liar, then you’re not to be trusted. If you’re a liar, then nobody will tell you precious information. Nobody wants to be friends with liars. Nobody wants to work with liars. And nobody wants to associate themselves with the lying kind. This is all to say it’s a pretty serious accusation to level at someone, especially someone you work with. 

It’s especially dangerous when your accusations are baseless. It’s like law 101 that if you’re going to accuse someone, you should have some hard evidence to back it up. But this doesn’t stop everyone. Some folks just want to watch the world burn and don’t care who goes down with them.