For a man who's such a genius, Doc Brown is certainly capable of some supernaturally bad decisions. Promising to build a bomb for Libyan nationalists, then delivering casing filled with pinball parts, as though they weren't going to figure that out almost immediately? Not a stellar move. But he is a great friend to Marty, no matter how many questions viewers may have about their relationship. How did they meet, anyway? And why are a high school musician and a middle-aged scientist willingly spending time with one another? Before the whole time travel issue came about, what did these two individuals have to talk about on a Saturday afternoon? It's never really explained. Regardless, Doc Brown is always there to help Marty with any and all of his time travel related, worryingly paradoxical scrapes (even the ones that are his fault).