The movie Back to the Future is a 1985 American science-fiction adventure comedy film (is that enough genres?) starring Michael J. Fox as a teenager named Marty McFly and Christopher Lloyd as an eccentric scientist named Dr. Emmett Brown. Dr. Brown, nicknamed "Doc" by Marty, creates a time-traveling car which accidentally transports Marty from the year 1985 to 1955. During this he accidentally becomes his mother's love interest, leaving it up to him to save the existence of himself and his siblings, while trying to get... back to the future. Ranked among one of the top ten films to see before you die, there's a reason why the Library of Congress chose to preserve this gem.
1. Who needs roads?
Dr. Emmett Brown: Roads?!? Where we're going, we don't need roads.
President Ronald Reagan loved this quote enough to use it in his 1986 State of the Union Address. Who says every day needs to be the same? Mix it up every once in a while. This is not suggesting that you try to go off-roading with your car. Drive safely.
2. Don't be afraid to make mistakes, it'll work out in the end
George McFly: Lorraine, my density has brought me to you.
Lorraine Baines: What?
George McFly: Oh, what I meant to say was...
Lorraine Baines: Wait a minute, don't I know you from somewhere?
George McFly: Yes. Yes. I'm George, George McFly. I'm your density. I mean... your destiny.
You could interpret this as a rough first impression. However, it still worked out for George and he got the girl of his dreams.
3. The Future Doesn't Have to Be Heavy
Marty McFly: Whoa, this is heavy.
Dr. Emmett Brown: There's that word again; "heavy." Why are things so heavy in the future? Is there a problem with the earth's gravitational pull?
Nope, there isn't anything wrong with the earth's gravitational pull. The future doesn't have to be heavy, it's entirely up to you. You decide your density... I mean destiny!
4. Put your own spin on it
Dr. Emmett Brown: The way I see it, if you're gonna build a time machine into a car, why not do it with some style?
Why do that one project like everyone else? It's boring for you and the people who have to look at it. Keep things interesting. Trust me, people remember the DeLorean, not the Chevy Nova George McFly drives before Marty changed his family's future.
5. Anything Goldie Wilson says in this scene:
Goldie Wilson: Stand tall, boy. Have some respect for yourself. Don't you know, if you let people walk over you now, they'll be walking over you for the rest of your life. Look at me. You think I'm gonna spend the rest of my life in this slop house?
...
Goldie Wilson: You wait and see, Mr. Caruthers. I WILL be mayor! I'll be the most powerful man in Hill Valley, and I'm gonna clean up this town.
Mr. Caruthers: Good. You can start by sweeping the floor.
Goldie is a guy with vision. He saw his future and went after it. Also, he pretty much predicted the future George McFly had when he didn't stand up for himself against Biff. I'd take his advice.
6. Don't listen to Mr. Strickland
Mr. Strickland: I noticed your band is on the roster for the dance auditions after school today. Why even bother, McFly? You don't have a chance, you're too much like your old man. No McFly ever amounted to anything in the history of Hill Valley!
Marty McFly: Yeah, well, history is gonna change.
Have Marty McFly's attitude. There's a reason no one ever liked Strickland. 
7. Even if it's a slim chance, it's still possible
Dr. Emmett Brown: This is it! This is the answer. It says here... that a bolt of lightning is going to strike the clock tower at precisely 10:04 pm, next Saturday night! If... If we could somehow... harness this lightning... channel it... into the flux capacitor... it just might work. Next Saturday night, we're sending you back to the future!
Don't be afraid to take chances. If Marty McFly could return to 1985 even after the cords connecting the lightning power to the car disconnected, then you can do anything. You miss 100% of the shots you don't take.
8. The Most Important One of All...
George McFly: Like I've always told you, you put your mind to it, you can accomplish anything.
This one pretty much explains itself.
