In Shakespeare's Romeo and Juliet, it can be argued that the young lovers would have had very different fates had they made better choices—keeping a hold on their anger.
Romeo is rather young—it is estimated that he is only about sixteen years old. When his friend Mercutio (who is also the Prince's kinsman) is killed by the bad-tempered Tybalt—as a result of the two men trading insults—Romeo loses his composure.
Alive in triumph, and Mercutio slain?
Away to heaven respective lenity,
And fire-ey'd fury be my conduct now!
Now, Tybalt, take the ‘villain’ back again
That late thou gavest me; for Mercutio's soul
Is but a little way above our heads,
Staying for thine to keep him company.
Either thou or I, or both, must go with him. (III.i.123-130)
Romeo throws his desire for peace to the wind and challenges Tybalt on Mercutio's behalf. He breaks the law in killing Tybalt (who is also Juliet's cousin), and is punished. While the penalty is supposed to be death, Escalus shows mercy and banishes Romeo from Mantua. This is not the end of the world, but Romeo is too immature to be patient and wait. Sadly, being reunited with Juliet would not have been at all impossible, but Romeo lets his emotions get the best of him.
Juliet, on the other hand, is generally more level-headed. When Juliet's parents try to force Juliet to marry Paris (which she cannot do: she does not love him, but she is also married to Romeo), the nurse mistakenly tells Juliet that it might be easier to marry Paris and forget Romeo—who she may never see and/or never be with. She notes that Paris is a much better man: Romeo is like a dishrag compared to Paris. (I believe the nurse does this to make Juliet feel better.)
Faith, here it is.
Romeo is banish'd; and all the world to nothing
That he dares ne'er come back to challenge you;
Or if he do, it needs must be by stealth.
Then, since the case so stands as now it doth,
I think it best you married with the County.
O, he's a lovely gentleman!
Romeo's a dishclout to him. (III.v.222-229)
So when Juliet and Friar Lawrence come up with a plan to fake Juliet's death, she turns her back on her nurse who has been with her since she was born. The nurse stands up for Juliet when her parents threaten to throw her out into the streets if Juliet does not marry Romeo. In her fury over what she perceives as the nurse's betrayal, Juliet shuts the nurse out of her plans regarding Romeo. Just before she is ready to drink the friar's sleeping potion, she ask the nurse and Lady Capulet to leave the room so she can sleep alone the evening before her wedding. The nurse's devotion to Juliet is seen when she finds Juliet "dead" the next morning.
Like Romeo, Juliet also lets her anger get the best of her. Had the nurse known of Juliet and Friar Lawrence's plan, the nurse would most probably have been at the tomb waiting for her charge to wake up, and would then have been able to tell Romeo what was happening. Romeo and Juliet would most likely have survived and left Verona to make a life elsewhere.