This so-called "Perfect Evening" was so disappointing that it discouraged us from coming to your Circle Theatre again.

so-called 是由 so（如此）和 called（被称作）组成的复合形容词，字面意思是"被如此称呼的"，通常带有讽刺或怀疑的意味，表示"所谓的"（暗指实际情况可能并非如此）。