If you could go back in time to see someone who would u choose

Dead or alive, maybe it's leo when he was younger, maybe your dad seconds before passing. Who, when, and why?
For me it's obv Robin Williams cause he's the manI would go back in time to save him from hanging himself, and I would hug him and we would cry, because life is oh such a hard thing, you just gotta find that little spark of madness. I would go back in time to prevent him from ever losing it.