Romeo and Juliet is a sneaky play. The literary term for this is dramatic irony. Dramatic irony means we get to know more than what some of the characters on stage know. For example, we know what houses Romeo and Juliet are from before they do, we know their secret love when just about all of the characters don't, and we know that every line of Juliet's to her parents can be taken in more than one way or is a lie.

Just about every time Shakespeare reveals a major detail, things begin to move faster, this is a feature of plot. Each complication is a moment of rising action. For example, in the end of Act I, after Romeo and Juliet kiss, they part. The nurse reveals quickly to each their fate.

Juliet's reveal:

JULIET 
What's he that follows there, that would not dance?

Nurse 
I know not.

JULIET 
Go ask his name: if he be married.
My grave is like to be my wedding bed.

Nurse 
His name is Romeo, and a Montague;
The only son of your great enemy.

JULIET 
My only love sprung from my only hate!
Too early seen unknown, and known too late!

And Romeo's reveal:

ROMEO 
What is her mother?

Nurse 
Marry, bachelor,
Her mother is the lady of the house,
And a good lady, and a wise and virtuous
I nursed her daughter, that you talk'd withal;
I tell you, he that can lay hold of her
Shall have the chinks.

ROMEO 
Is she a Capulet?
O dear account! my life is my foe's debt.

Each of these takes place with some short sets of lines. These are traumatic and very dynamic positions in the text.

In the opening scene of the first act of Romeo and Juliet, the staccato exchange of hostilities between Sampson and Gregory, of the House of Capulet, with Abraham, a servant of the Montagues, serves well to create tension and effectively set the tone of animosity between the two families.

Again, the brief, but acrid verbal exchange between Mercutio and Tybalt in Act III suggests that action will soon follow as, obviously, the usually loquacious Mercutio is not interested in talking in this scene:

Benvolio:  By my head, here come the Capulets.

Mercutio:  By my heel, I care not.

Tybalt:  Follow me close, for I will speak to them.

Gentlemen, good-den--a word with one of you.

Mercutio:  And but one word with one of us?  Couple it with something--make it a word and a blow

Tybalt:  you shall find me apt enough to that, sir, an you will give me occasion.

Mercutio:  Could ou not take some occasion without giving? (III,i,26-32)

Not only are the exchanges brief, but the tone and implication of meaning are extremely hostile.  With words, Mercutio and Tybalt warm up for the sword fight.