In the interest of mental health and wanting to be a class act, I ask, "When is it right to give someone your book?" Some provisional answers, from experience:
1. Give it when the recipient will care about it. You have friends who don't care a fig about your poetry. Do not attend their birthday parties and, with shining eyes, gift them with your poetry book.
2. Do not give it as a prize or premium, or instead of compensation for services, or as a thank-you, unless you are thanking the recipient for somehow helping in the book's creation or promotion. Do not withhold the book from anyone who helped.
3. Do not give your book as a substitute for a real gift, or as an act of charity unless the charity solicits it.
4. Do not try to impress a non-writing romantic interest, or his or her parents, by giving your book. If you are female they will say behind your back that you are siddity (stuck-up, think you are too good for them); if you are male they will say the writer thing is okay but he'll never make any money with it.
5. Yes, give your book in exchange for another writer's book.
6. Give it to a potential reviewer, but when no review appears, don't pin her to the wall and demand to know what happened.
6.5. Don't give it to people you ignore except when you want their attention for your book.
7. Don't give it unless you give it with all your heart. If you'd really like money for it, tell them you'll sell it to them for cost. Really. Or the transaction will embitter you.
8. Don't give it to someone who really should buy it, such as a stranger chatting you up at a book signing.
9. Give it to a famous writer if you like, but do not expect it to be read, because he or she gets handed books all the time, and do not expect thanks. Hope only that he or she glances at it and says, "Doesn't look bad," or "That'd be nice to read if I wasn't so busy writing."
10. Give it to someone who will share the joy of it with you.