Liane Moriarty said this quote
“ Toxic' was actually an accurate description of the feelings Clementine had so often felt in Erika's presence: the intense aggravation she had to work so hard to resist and conceal, the disappointment with herself, because Erika wasn't evil or cruel or stupid, she was simply annoying, and Clementine's response to her annoyingness was so completely disporportionate, it embarassed and confounded her. Erika loved Clementine. She'd do anything for her. So why did she inflame Clementine so? It was like she was allergic to her. ”