The nerd in me was always bothered by what appeared to be a gaping plot hole in Back to the Future Part II. When the Biff from 2015 traveled back in time to give his younger counterpart the Sports Almanac, old Biff returned to what appeared to be an unaltered 2015. However, as Doc points out later in the film, the future was also necessarily altered when young Biff obtained the Sports Almanac. So, how could Old Biff return to 2015 to drop off the DeLorean?
Once again, the solution is far simpler than the original problem. From the Wikipedia:
Many fans have debated as to why Marty and Doc didn’t notice 2015 changing around them into 2015-A, and the conclusion has been that 2015-A’s Hilldale streetcorner just wasn’t noticably [sic] different from the normal one. Had the time travelers gone into town, they probably would have noticed drastic changes in the cityscape, much like there was in 1985-A’s town square, compared to the exterior of Marty’s house.
Thank goodness. I can finally get a good night’s sleep now!
(Incidentally, I contemplated creating a new category for this post… something to the effect of “ultra geeky.” That would just be a hassle though. So, geeky it is.)