This is so true. It applies to most written communications, electronic or otherwise. People will pour their own emotions in the written word, and it doesn’t matter how many emojis or sarcmarks you put.
I'm in a vaguely bad mood because of something somebody said to me on Twitter. It's not fair, but it's totally expected. Bear in mind that when you say thing to people on Twitter they will react emotionally. Don't overlook the power of your words.