Due to the effects of SMILE, Toko is unable to express any negative emotions. She constantly laughs, even when she is overcome with grief, such as during her father's execution. She has no self-control over her laughter, 
However, while she cannot express negative emotion she is still often genuinely happy and friendly. She likes to make jokes, especially about her name. She is a very friendly little girl who will readily show gratitude, (she can never stop laughing or smiling)