Daniel offers a headline that says he thought the day couldn't get worse, but he was wrong. When he walks into Dae Hyun's store, his dad is busy but shoots Daniel a look that says there will be a conversation later. Daniel finds Charlie locked in the stockroom. Charlie sneers and makes a show of looking for Natasha. Daniel knows that Charlie is baiting him, but he doesn't back down. He tells Charlie that he came to ask him a question, and ignores Charlie's jabs to ask him what happened to make Charlie hate him.
The fact that Daniel is looking specifically for a reason for Charlie's animosity suggests that he desperately wants the perspective of time to make sense of their relationship. This shows Daniel attempting to make more sense of a deterministic way of looking at fate and the world, which suggests he's taking Natasha's beliefs to heart.
Charlie is surprised, but he just insults Daniel's appearance and asks him about his interview for the "Second-Best School." Daniel admits he doesn't even want to go to Yale and realizes Dae Hyun is behind him, listening. When the doorbell chimes Dae Hyun returns to the front of the store. Charlie insists he's just stronger, smarter, and better than Daniel. When Daniel asks Charlie if it turned out that he wasn't better than all his classmates at Harvard, Charlie's clenched jaw tells Daniel that he hit home.
For Dae Hyun, hearing that Daniel doesn't share his version of the American dream is likely an earthshattering moment. This suggests that Dae Hyun will be forced to continue the process he's already begun of recognizing that both of his sons aren't the perfect Korean men he hoped to raise; the US is a part of them and has influenced their desires in meaningful ways.
Charlie gets close to Daniel and tells him that he doesn't like him because he's too Korean—he spits that they're not even from Korea, but it seems like Daniel is only Korean. Daniel is stunned and he discovers he pities Charlie, which makes Charlie even angrier. Charlie grabs Daniel by the collar and rants that nobody's going to treat him different because he writes poetry and dates a black girl. Daniel punches Charlie in the face. Charlie rushes Daniel, punches him in the stomach and the face, and only stops when Daniel knees him in the groin and Dae Hyun enters, yelling in Korean.
Charlie sees his immigrant history as keeping him from being truly American—and that's something that's extremely difficult and offensive for him to live with. In Daniel's case, that same thing is annoying, but not life-ending. This shows again that the immigrant experience and the American dream manifest differently for all immigrants, and everyone deals with the challenges of trying to be American differently.