A few years ago I had a classmate who was rudely terse in his replies to group emails. For instance, if someone asked, "Here is my understanding of blah blah. Is this correct?" This person would reply to all with only the word: "No."<p>I was surprised to eventually learn that the person behind these weird emails was the friendliest student in the class. Apparently he just wasn't used to emailing. To him, "no" was equivalent to "No, sorry, I don't think that's quite right. I'll try to follow up shortly with a more detailed answer."