As a science fiction movie, Back to the Future should be terrible. It takes tremendous liberties with its "science" and its plot has more holes than a box of donuts. Here are just a few problems I have with the story:

• The very first time you try out your time machine, you don't stand directly in front of a car going eighty-eight miles per hour and say, "If my calculations are correct..."
• All they know is that lightning struck during the 10:04 minute: there would be no way to know the exact split-second when lightning hit. The odds of their plan working could be as bad as one in three hundred. To guarantee they get their 1.21 gigawatts they would have to build a rail about 1.5 miles long and hook the DeLorean up to it like a streetcar. Then as long as the DeLorean is going 88 mph that entire minute, no matter when the lightning strikes, they'll get their electric jolt. Doc really should have seen that coming.
• If you prevented your parents from meeting, there is no reasonable explanation for a photograph of you, your sister, and half your brother. On the one hand, if anyone would disappear, it would be Marty first (as he's the youngest child and thus the furthest down the timeline from his parents' meeting). On the other hand, people don't partially disappear. At no point would you find his brother walking around with half his body missing and posing for a photograph.
• And let's face it, Marty should have been killed when he struck that opening guitar chord.

I could go on but you get the point. Actually, no, you don't get the point because I haven't actually made my point yet. My point is: in spite of all that, it's a really good story and very well-executed movie (currently #70 on IMDb's Top 250). Who cares if the science doesn't make any sense? That's not the purpose of the film. The purpose of the film is to entertain, and on that level, Back to the Future hits one out of the park.

Bob Gale and Robert Zemeckis knew that the story was paramount. I, on the other hand, can't seem to grasp that. I'm the type that would spend weeks working out the exact science. My version wouldn't have a single plot hole and consequently my version wouldn't find a soul on earth who would care to read it.

I'd invest all my energy into the back story and completely forget that I was supposed to be telling a front story. Who cares if Marty's hand becomes semi-transparent while playing the guitar? The audience is enjoying the story. And they're extremely adept at suspending disbelief if the disbelief is dispensed the right way.

The wrong way is forcing them through forty pages of (what amounts to) science lessons just to ensure everyone "gets it" before you tackle the pesky task of writing an engrossing story.

On the upside, I've heard that recognizing you have a problem is the first step to curing it. So at least I've got that going for me.