It's always fun trying to think about time travel, and the way people always say "where are all the time travellers?" (if they are here and now, then they're not exactly going to make themselves known, are they?
), but when it gets to the point of correcting past errors, that's where the headaches begin, such as correcting say a car crash that you thought should never happen, you travel back, prevent it happening, and the future's changed, but, because you change the future, then you had no need to travel back to fix the past, so the time travel never took place and therefore the crash occurred again, it's basically the self-correction paradox, and really is a headache-inducer...
Travelling into the future would be interesting though, seeing what will happen and potentially steering the future in a different direction, this would work compared to the above as the travel occurred in the past, then to the future, then back again, so that the the future can be rewritten because it hasn't happened yet so the self-correction paradox doesn't take hold, in theory...
And of course there's the paradox I forget the name of where something has never been created but has always existed, such as in BTTF where in 1955, Marty plays Johnny B. Goode and Chuck Berry's cousin Marvin plays it to him down the phone, so Chuck releases it, then in the future, the younger Marty learns the song then later travels back to 1955, continuing that temporal loop of something that never was created, but has always existed........
Right, I need to find my paracetamol before my head explodes....