I'm only here for the beer.

The line is a blunt, comic declaration of minimal commitment: the speaker disavows any higher purpose—socializing, networking, celebration, or ideology—and reduces their presence to a single, tangible incentive. Its humor comes from deflating whatever earnestness the occasion might claim, and from the implied honesty (or performative honesty) of admitting a self-interested motive. As a quotation, it functions well as a wry caption for parties, meetings, or events where attendance feels obligatory; it also gestures toward a broader skepticism about social rituals and the polite fictions people use to justify participation.