If You Could Time Travel Back in Time - What Would You Do?

If you could go back in time, what would you change or do? and why?...First we need to think about to what age we would like to go back to, because going too far back in time could lead to our certain death. The ancient times were known to be pretty heavy aggressive times, so lets go back a little bit...to the year 2009.

Why 2009 you ask? Because of a very particular factor happening in that year, the bitcoin. If i could go back in time i would surely invest in bitcoin when it was worth 0,79 cents, if i had discovered back then what i know now, i would be a rich man no wonder, but yeah, life doesn't work that way.

Going back to the Tardis...( From Doctor Who Series )

I know many with a Tardis would like to go back and stop bad things from happening, but if there is something i learned watching Doctor Who is that no matter what you do, somethings are just bound to happen no matter what and could potentially lead to a time travel paradox.

A time travel paradox is basically a loop or a specific event in spacetime, for example, the "Let’s Kill Hitler Paradox", if you could go back and kill Hitler, if you were succesful however, that would have far reaching consequences for people in the entire world, even the fact that you studied about him in school would disappear, with no Hitler in the history, you wouldn't have the idea to travel back in time in the first place. If you killed Hitler then none of his actions would make you do such attempt to go back in time.

So, if i could apply that to my question above, of the bitcoin, going back in time to invest in bitcoin in 2009 would mean that could change my future and denying the possibility of going back in time for that specific reason in the first place.

I guess i should just agree with Doctor Who and leave all this time-travelling to the Time Lords, its too much confusion and we humans don't know how much damage it could potentially do.

What about you, what would you do if you could go back in time?