If you were able to do one thing it would be what? It can be anything....yourself , the world, your life, your past or whatever.
Now you've started the butterfly effect... I was thinking more fictional, like flying or have enhanced vision. (Vision being more confidential).
I was so fortunate to see him live in Vancouver. He did a speech and when he walked into the auditorium, it instantly changed and was so wonderful. Love to see him again.
ANYTHING? I'd give my entire life a mulligan from about 23 years old. I had a series of 'backing the wrong horse' scenarios and had no guidance. Literally won and lost fortunes. BOY, that would be different.