NOKW - Back to the Future

Here comes the next chapter in our "I'm Okay With, I'm Not Okay With" series (if you don't know what this is, click here for all of the past posts):

Movie:  Back to the Future

Basic Plot:  A crazy scientist invites time travel and a teenager accidentally gets stuck 30 years in the past only to almost undo himself by changing stuff, but ultimately fixes things and makes his future life better.

I'm Okay With:  The fact that why a car has to go 88 miles per hour in order for the flux capacitor to work is never explained.  The fact that Doc knew Libyan terrorists and though it would be a good idea to steal freaking plutonium from them   The fact that those some Libyan terrorists actually had plutonium and weren't using it to do terrorist-y things with it.  The fact that Biff isn't in jail for any one of the numerous crimes he commits throughout the movie, the worst of course being attempted rape.  That fact that this site will probably be red-flagged because I have now mentioned terrorists, plutonium, and rape in the same post.  The fact that the future is not changed any more than it is considering that Marty does introduce rock music many years before it actually hits the air.  The fact that when he shows up in the future and his family is now no longer dysfunctional, he still technically is and therefore should be looked at as insane by the rest of his family.

I'm Not Okay With:  The fact that Marty and the Doc are even friends to begin with.  How many old eccentric people are you friends with that are not family or family of your best friends?  The answer is none.  So how did Marty and Doc even meet in the first place let alone have enough in common to become friends?  It's not like Marty is a brilliant science prodigy or master inventor savant, he is just a punk high school kid who wears a puffy vest all the time and doesn't like to be called "yellow" for some reason.  And it's not like Marty is an outcast at school and has to make friends wherever he can, he has a hot girlfriend and if he was bored he should probably be spending more time trying to get into her pants.  Which brings me back to the point at hand, why are Marty and Doc good enough friends that Doc would show him the most earth-shattering scientific discovery in history?  There is no explainable reason unless they forgot to mention that Doc is actually Marty's crazy uncle or grandfather or something, but that is not the case.  I am not okay with that.

"The fact that this should be the real result of time travel."