Back to the Future 2

The time-traveling is just too dangerous. Better that I devote myself to study the other great mystery of the universe: women!

— Well, thanks. Nice talking to you. Maybe we'll bump into each other sometime again in the future.
— Or in the past.

— When I have kids, I'm gonna let 'em do anything they want. Anything at all.
— I'd like to have that in writing.
— Yeah, me too.

2015? You mean we're in the future?

— Oh, this is heavy, Doc. I mean, it's like I was just here yesterday.
— You were here yesterday, Marty.

Who you calling butthead, butthead?

— Doc! Doc, come in!
— Marty, come in.
— Listen, Biff's guys chased me into the gym and they're gonna jump... me.
— Then get out of there!
— No, Doc, not me. The other me. The one that's up on stage playing «Johnny B. Goode».
— Great Scott! Your other self will miss the lightning bolt. You won't get back to the future and we'll have a major paradox!
— Wait. A paradox? You mean one of those things that can destroy the universe?
— Precisely.

— Jennifer could conceivably encounter... her future self. The consequences of that could be disastrous.
— Doc, what do you mean?
— I foresee two possibilities. One, coming face to face with herself 30 years older... would put her into shock, and she'd simply pass out, or two, the encounter could create a time paradox, the results of which could cause a chain reaction that would unravel the very fabric of the space-time continuum and destroy the entire universe. Granted, that's a worst-case scenario. The destruction might, in fact, be very localized, limited to merely our own galaxy.
— Well, that's a relief.

— That's right, Doc. November 12, 1955.
— Unbelievable that old Biff could have chosen that particular date. It could mean that that point in time inherently contains... some sort of cosmic significance, almost as if it were the temporal junction point... for the entire the space-time continuum. On the other hand, it could just be an amazing coincidence.

— «Within two hours of his arrest, Martin McFly Jr... was tried, convicted and sentenced to 15 years in a state penitentiary». Within two hours?!
— The justice system works swiftly in the future now that they've abolished all lawyers.