This sort of scenario has happened, I imagine, millions of times. It has rarely happened in a nicer, sweeter, more gentle way than in Richard Linklater's "Before Sunrise," which I could call a "Love Affair" for Generation X, except that Jesse and Celine stand outside their generation, and especially outside its boring insistence on being bored.
The R rating for this film, based on a few four-letter words, is entirely unjustified. It is an ideal film for teenagers.