This quote refers to Changez learning about American culture. To him, having a meeting with a beautiful girl means that he should present himself well; so, he shows up in a nice outfit. But he is taken back a bit by the fact that Erica was only wearing a "Mighty Mouse T-shirt" and this is where he inserts the above-mentioned quote (50). For Erica, she's just hanging out at her place with a friend, but for Changez, it's a date, or at least a very important person for whom he wishes to be well-dressed. The miscommunication about dress is one founded upon different experiences and backgrounds because Changez and Erica are from different countries. Ironically, Changez feels at home in Erica's place because it represents much of the same quality of life that he left back home to become an student in America.