it is a terrible thing to say to someone with cancer that their attitude matters and that they should stay positive, because it does two things: For one, it puts the responsibility of healing and surviving on the sick person. It implies that if you don’t win the fight and have faced the gravest of all outcomes, it is your fault. That if you just had been more positive and optimistic, no matter how you really felt, that you could have saved yourself. Which is an incredibly unfair burden to put on someone who is fighting this disease.
