There's a lot of things I wish didn't exist.
1. Nasty People
2. Countries I don't like. (E.g The US, The Middle East)
3. Religions which promote abuse, disregard for human rights and so on. (E.g Christianity)
4. Prejudice against certain races, sexualities and so on.
5. For mental illnesses to be gone , as sad as it sounds I'm not 100% against physical illnesses because overpopulation is an issue, who knows I might change my mind when I'm on my death bed while suffering from cancer, if I even make it that far in life.