The first time I walked into a store, the clerk screamed out some greeting. I thought he said, "Good morning". This was a little odd because it was 2 in the afternoon. But being polite, I responded back with, "Good morning." Only later did I discover that he wasn't saying, "good morning", but the Chinese for, "Welcome" (歡迎光臨 Huānyíng guānglín, ㄏㄨㄢㄧㄥˊㄍㄨㄤㄌㄧㄣˊ) . This is customary at most stores. At some stores, like clothing stores, they will also tell you to "have a look" (看看Kàn kàn ㄎㄢˋㄎㄢˋ)