In Buffy The Vampire Slayer Joss Whedon communicates important themes that are relevant in our society. The most prominent of the these is the topic of Feminism versus the Patriarchy and of teenage worries, both of which are evident through the interactions of the characters.
The Feminism versus Patriarchy theme is evident through the characters of the show and how they are represented as either "feminist friendly" or "patriarchal friendly". The villains of the show, such as the vampires in "Welcome to the Hellmouth" and "The Harvest", represent patriarchal friendliness through their trying to take over the earth for themselves, and to infect others to become fellow vampires, or spread the patriarchal "virus".
The characters of Buffy provide evidence for the fact that Joss is presenting the topic of Feminism versus the Patriarchy through their attitudes, behaviour and actions. In the first two episodes Luke and Darla, the vampires, both represent patriarchy friendly gender models. Luke is shown as dominant, aggressive and overpowering. He does the Master's (who represents the Patriarchy as a whole) bidding as his Vessel and attacks others, killing or otherwise infecting them with the virus. Darla is portrayed as patriarchal friendly though her obedient, submissive behaviour. She also wishes to spread the virus, for example when she infected Jesse, who became a patriarchal friendly vampire. Buffy, Xander, Willow and Giles are feminist friendly, which is evident through their actions to protect their friends and others from the dangers of the supernatural world, that represents the patriarchy, they are unaware of.
In addition to this, teenage worries, such as bullying and relationships with family and peers is a key theme through the Buffy series. This is shown through Buffy and her friend's interactions with others. Evidence for this is present in "The Pack" when the pack in question are walking around the Zoo on a field trip, making fun of other students and hassling them. They even take it as far as pushing another classmate up against the Hyena cage and threaten to push him into the pit.
For Buffy, the stress of relationships with her parents and with her peers comes with her being a Vampire Slayer, and not being able to tell them. It causes her peers to make judgements about her and look down on her, calling her "weird" and other things of the sort, as for lack of any other explanation for her odd behaviour. An example of how her being a Slayer affects her relationship with her parents is in "The Harvest" when Buffy's mother sees Buffy's urgency as a teenage phase, stating "Everything is life or death when you're a sixteen-year-old girl," which gives a sense of belittlement to Buffy and not taking her seriously, which adds to the strain of having a good relationship with her.
Joss has communicated these different themes in Buffy using the main group of character's interactions with villains and other students, using subtext, such as with those characters who represent the patriarchy, and in more obvious ways, such with the schoolyard bullies in "The Pack".