"What is the book that changed your life? (not novels or religious texts)"
I think it's a wonderful way to connect in a less superficial way and learn a little more about each other. It's also a wonderful way to discover new books worth reading.
This is one of them (the full list is here):
In this thoroughly revised, updated edition of his classic "Language in Thought and Action, " S.I. Hayakawa discusses the role of language in human life, the many functions of language, and how language - sometimes without our knowing - shapes our thinking. The author writes provocatively about the relationship between language and racial and religious prejudice; about the nature and dangers of advertising, from a linguistic point of view; and, in a completely new chapter called "The Empty Eye, " about the content, form, and hidden message of television, from situation comedies to news coverage to political advertising.