When a friend gives me a book - whether they just think I'll enjoy it or they ask me to read it because they are curious about how I will recieve it - I try my very best to read it. There is something oddly special to me about sharing the written word with someone that I just don't take for granted. Certainly, I may not enjoy the book. I may disagree with it or find it hatefully boring. That's life, but I'll still read it and do my best to take it all in and for it, I hope, I'm a more full person.
When I give a book to another person I, perhaps unfairly, expect the same sort of respect. I don't share what I read with everybody (sans news articles and such linked here, obviously) so when I do it means something to me. I'm sharing it because I think there might be something the person can gain, or more often something the person can help me with, something the person can explain about the book or story, something they can clarify. It's almost like a personal favour that I'm asking and just as I feel I owe any good friend an honest opinion when asked - whether they will like it or not - I wish I could receive the same in return.
On occasion, a friend will tell me that they just don't read much, or that they probably won't get to it since they have a pile of shit they gotta read already. That's fine - upfront and honest - and not something I take offense at. What I do take offense at is people feigning interest and making hollow promises. If there is anything I can respect it's honesty and integrity. Otherwise it's just a lie.