Love. What is love? How it's defined depends on who's talking and what the situation is.
Bawdy. Knowing references to sex, usually humorous. Critics say the bawdy serves to highlight, by contrast, the love of Romeo and Juliet, which is both sensual and innocent.
Light and Dark. From the first scene to the last, the play is filled with contrasts of light and dark.
High and Low. There are two balcony scenes, the long one on the night of Romeo and Juliet's first meeting, and a very brief one the morning the lovers last see each other alive. In the first Romeo speaks as though he would fly up to Juliet; in the second, Juliet speaks as though he has fallen into a pit from which he may never return. In addition to these striking stage-pictures, the contrast between high and low is often made metaphorically.
Speed. Almost everything happens very quickly, and the characters often mention the speed of events. (The impression of speed is also created by the frequent indications of the times of events. For a list of these indications, see the Chronology.)
Foreshadowing. The Chorus calls Romeo and Juliet "star-cross'd," and the frequent foreshadowing of the lovers' fate creates the sense that destiny will have its way.
Stars. The stars, which shed the light of love, also hold the lovers' destiny.
Sweet Sorrow. The play ends with the lovers dying in one another's arms, and throughout the play it's often said that joy and sorrow keep close company.
The Marriage of Love and Death. The culmination of sweet sorrow is the love in death of Romeo and Juliet. Some metaphors refer to her as the bride of death, but in the end, their marriage outlasts death.
Youth and Age. In Shakespeare's source, Juliet was sixteen. Shakespeare reduces her age to thirteen and repeatedly emphasizes the differences between the old and young.
Parenthood. Not as seen on TV: Shakespeare's parents are neither supremely wise, nor clueless boobs.
The Feud. The first words of the play speak of the feud's disruption of civic order, and the play ends with the end of the feud and the restoration of civic order.
Names. How much does a name tell us? Juliet says, "a rose by any other name would smell as sweet," but others seem to think that the name of something is all that matters.