Why does my girlfriend like to call me the devil

Explain that you are dissatisfied with her in some way, or just a joke she played!

For example, you are a little clumsy, slow-witted, have some bad hobbies and so on. Or you can be called a little devil. In short, she called you that with some kind of joke. If you have something bad, I hope you can take the initiative to correct it and make yourself more attractive. Come on!