The thing is I smile and laugh a lot with my students. We joke a lot and have fun (they range from 4 years old to 11). It's the parents who think I'm all serious and scary and it takes time before they learn from their kids what fun we have in the class (unless they eavesdrop and hear us laughing in the classroom
So the problem is with my vertical wrinkle between my eyebrows, making me look angry, not with my lack of making the kids laugh
And the kids of that age don't care whether I'm ugly or not. For them I'm just magical: not black hair, not black eyes, a long and narrow nose, etc. (I teach local kids in Hong Kong).