Marty, why are you so nervous?
Lorraine, have you ever, uh, been in a situation where you knew you had to act a certain way, but when you got there, you didn't know if you could go through with it?
You mean, like how you're supposed to act on a first date?
Well, sort of.
Oh, I, I think I know exactly what you mean.
Y-y-you do?
You know what I do in those situations?
What?
I don't worry. [kisses him hard, then stops and pulls back to see Marty is shocked] This is all wrong. I don't know what it is, but when I kiss you, it's like I'm kissing... my brother. I guess that doesn't make any sense, does it?
Believe me, it makes perfect sense.