The greatest fun, travelling backwards in the past, takes place in my imagination. Just like you did here, it's a great pleasure to take on certain scenarios and sense that the whole thing would be less straightforward. Dancing around in a past as a knowledgeable person alone would probably even be quite dangerous. If you love the risk of losing your life in the process, you might also tend to live a risky lifestyle in your present.
I wouldn't want to save anyone. But of course, if I were stuffed with knowledge and compassion came over me in a current situation, I would instinctively want to save. So it's a good thing this won't work.

One thing I really would have liked to have been part of is the journey to the moon in a spaceship. To experience the universe in a small nutshell out there, that would certainly be something. But where would I be able to hide? In addition I would probably need a quite large vomit bag :)

Other than that: I am not a believer of saving people from the bad things happened to them. If so, you'd have to save all of them. Now, that's a total different scenario.

Great question you asked!