Basically everything and anything to do with mental health/psychology. People with Dissociative Identity Disorder (or "Multiple Personality Disorder" as it used to be known) do not have "evil" alters. DID is also not the same thing as schizophrenia. OCD is often not focused on hygiene or cleanliness. Antidepressants aren't "happy pills," and while emotional blunting is a possible side effect (not the entire point of taking the medication!), it's often a sign that you're on the wrong dose or the wrong medication. People don't typically self-harm because they're suicidal. Eating disorders don't always have a focus on body image and anyone of any body size can be affected. There's no singular mental illness that causes people to be abusive or violent, and mentally ill people are more likely to be victims of violence than perpetrators. Etcetera.