We can see social codes at play in all of Shakespeare's plays.

Gender roles are a prevalent theme, and we can look at Shakespeare's plays to think about how women were perceived and treated in Elizabethan society. A Midsummer Night's dream begins with Hermia pleading with Theseus to let her marry Lysander, whom she loves. Her father, however, wants her to marry Demetrius. As a young girl in this society, Hermia is not free to make her own choice. She must follow her father's orders and marry Demetrius, take a vow of chastity at a convent, or die.

Juliet is in a similar situation where her father makes a match for her. He arranges for her to marry Paris, even though she just about to turn fourteen. When Juliet talks with her mother and her Nurse, they comment on how younger girls than she are already married with children. This shows us how it was common in that society for girls to be married off at a young age.

Brabantio assumes his daughter has been stolen by Othello, when in reality Desdemona fell in love with Othello and married him in secret. Othello also shows us racism in society, with many references to Othello's skin color and prejudices against him.

We can look at antisemitism in Elizabethan society through the character of Shylock. In The Merchant of Venice, he is portrayed as a villain, and must convert to Christianity in the end.

Shakespeare's plays reflect the social conditions and issues of the time through the characters and conflicts.

A recurring theme, especially in his comedies, was love and marriage.  Shakespeare reflected the culture and society of his day (and how it was changing) through his examination of the ways in which his characters decided or gained permission to marry and the ways in which love affected this choice.

In Shakespeare's day, love was still pretty inconsequential a factor when it came to marriage.  For the most part, marriages were still arranged by families as a sort of business deal or, if the families were important enough, a political alliance.

Love was not, generally speaking, the motivating force for marriage in the world around Shakespeare, yet in many of his plays (and most all of his comedies) lovers are attempting to defy parential or societal conventions and make their own decisions about whom they will marry based upon love and not social or political connection.  This was a very new idea at the end of the 16th and beginning of the 17th century, and, as such, was a fascinating subject for Shakespeare to examine in his plays.

Some of the examples of this in the plays that jump out are Romeo and Juliet in the play of the same title, Lysander and Hermia in A Midsummer Night's Dream, Helena and Bertram in All's Well That Ends Well (in this case, Helena tries to manipulate political connections in order to marry for love), Valentine and Silvia in The Two Gentlemen of Verona, Othello and Desdemona in Othello, and Bianca and Lucentio in The Taming of the Shrew.  The list could go on, but this gives you an idea of how pervasive the theme of marrying for love versus social convention was in Shakespeare's plays.