Seriously, I'd change my eye. I was born blind in my right eye and it looks different to my other eye. Some people think it's a glass eye but it's not. Anyway, I'd change it so it looked normal so I'd stop having people stare at it.
Why limit yourself to one? For me: - not to be so quick to judge - to be more tolerant - to be able to forgive my parents - 40 years into my lifetime and 10+ years of therapy and I still can't find it in my heart - being able to admit when I'm wrong without being a dick about it - to be able to practice what I preach - to smile more