Me and this coworker have known each other for a year. Our relationship was a playful one and we tease each other. that's her humor, she has told me about it and she teases others (not as heavy as she does me) and they tease her back. Most of the teasing is about being lazy and not doing work, everybody does it. She was kind of in a bad mood the other day and she told me that I'm always insulting her and her work. I thought it was understood that it was playing, she is a great worker and that's why I tease her about it, but she told me that when I say it, makes her feel like she is doing a bad job. I never take any teasing seriously because we are always smiling and making eye contact, what's her deal now? Why is what I say such a big deal? She never tells that to other people.