That "just joking" dialogue was painful to see. After years of enduring that, I discovered it was a classic "verbal abuse" tactic. The abuser doesn't want to look like an ogre so he says what he thinks (or tries to get in a put down) and then passes it off with "I'm just joking". If the person is hurt, then it is now "you are too sensitive". Usually if someone says "Have you gained weight", or "Your cooking is bad", it isn't really meant as a "joke" - why would you ever say that to a great cook for example? It is a way of making a criticism, but not looking bad, because, after all, you are "just joking".