[WARNING: Here be spoilers!]
Gossip Girl Season III Episode 19
After 17 episodes of being the sweetest couple of the season, Chuck and Blair were too good to last. Breaking up became inevitable, and Blair was determined to leave the past behind her.
Despite Dorota's observation that "Miss Blair not yet grieve properly", Blair invited "a dozen of Manhattan's most eligible bachelors" to brunch, so "world can know Miss Blair single again and Chuck Bass thing of past". She also asked Dorota to toss out the "box of junk", containing the memories of her relationship with Chuck.
Unfortunately, none of the bachelors turned up. Blair assumed that Chuck had put a dating fatwa on her, but soon found out that no one on the Upper East Side thought they could measure up to what Chuck and Blair had. Blair then turned to a party in Brooklyn to find an unknowing guy to kiss. The idea was to get the photo splashed across Gossip Girl to break Chuck's fatwa.
And Chuck followed her. Blair did find a "sacrificial lamb", a Cameron from Columbia, and he was more than willing to help make Chuck jealous. But at the last minute, she decided not to go through with it.
'I suddenly realised that, the way to get over you wasn't by hooking up with some random guy, or pretending like we didn't happen. You and I loved each other, and then you broke my heart. I've been doing everything possible not to face that fact. I'm gonna kiss somebody someday. And when I do, it'll be for me. Goodbye Chuck.'
And when Dorota went to throw away the box of junk, she took it back.
'It's no use to deny the past. Chuck is a part of me. He'll always be. It just hurts so much.'
Then, one by one, she took out the items, bringing back their memories from the past.