The tone of people's voices tell you a lot about how someone's words are meant.
Written words don't hurt as much because you have to think before emotions get into the message that is sent.
Even the most unambiguous message can be read in many different ways.
What a person means is sometimes different from what a person says.
What a person thinks about a situation often affects what a person does which affects how the situation turns out.
With a different perspective & good communication skills you can sometimes turn these situations about.