All of those things require being inconsiderate . <| sep |> The crews of the Enola Gay and Bockscar . Yes , they killed thousands of people . But indirectly saved the lives of many . America would have commenced a large scale invasion of Japan using nukes and chemical weapons as it goes . Millions of people would ' ve died on each side as Japan began training their civilian population to use wooden pikes and Japan kept many advanced prototype tanks there just in case . <| sep |> Lol olynyk <| sep |> Sounds like Em C H 7 G to me . I ' m not really good at learning songs by ear so someone correct me if I ' m wrong please <| sep |> You are not <| sep |> Theoretically , any temporal incursion would do that . By being there , you ' ve changed the timeline even slightly , causing at least one person to be delayed . That delay would accumulate with delays to every other person they encounter , and so forth and so forth . That delay would also affect which sperm fertilizes which egg . Thus changing pretty much every birth after that point .