In Romeo and Juliet by William Shakespeare, the two young lovers seem to undergo more than their fair share of unfortunate accidents. In the Prologue, Shakespeare describes their fate as follows:
A pair of star-cross'd lovers take their life ...
"Star-crossed" in this context has an astrological significance, suggesting being born under the wrong stars and thus condemned to bad luck.
The first bit of bad luck the lovers undergo is falling in love with the most ineligible possible people. Thus Juliet laments:
O Romeo, Romeo! Wherefore art thou Romeo?
Deny thy father and refuse thy name.
Essentially, if the two young people had different parents, they could have married happily, but they happen to be children of families on the opposite sides of a feud.
The next part of bad luck has to do with the miscommunication concerning Friar Laurence's scheme. Romeo by accident does not get the note letting him know that Juliet has taken a sleeping potion and is not actually dead. Paris' fight with Romeo also has to do with a miscommunication.
As stated in the Prologue to the play, Romeo and Juliet are "star-crossed," meaning that they are beset by bad luck throughout the play. They have the bad fortune to fall in love in the first place, as they come from rival families. The Capulets and Montagues have a long-simmering feud that's not going to go away any time soon, and so the lovers must meet in secret.
In addition, Tybalt, who is a member of the Capulet family, tries to punish Romeo for having attended the Capulets' ball, the place where Romeo met Juliet. Tybalt winds up killing Mercutio, Romeo's friend, and Romeo slays Tybalt in reaction. Romeo, banished from the city of Verona as punishment for his crime, does not get the message that Friar Laurence has given Juliet a sleeping potion to make her appear dead and not need to marry Paris. Upon finding the sleeping Juliet, Romeo believes she is dead and kills himself by drinking poison. Juliet, finding Romeo dead when she awakes, slays herself. At every turn, the lovers meet with bad luck, in the form of feuding families, incensed relatives, and missed messages. Fate is not on their side.