Why it worked
This video likely worked because it taps into nostalgia for popular teen dramas like The O.C. and Gossip Girl, and plays on the perceived similarities or contrasts between iconic characters, which resonates with fans of the genre.
Summary
The video shows various clips of a woman, presumably Marissa Cooper from The O.C., with the text "who serena thought she was" overlaid. It then transitions to clips of Serena van der Woodsen from Gossip Girl, implying a comparison or connection between the two characters.