It also used to give me tremendous pleasure giving a friend, a colleague or even a random encounter a book I myself had enjoyed at some point, although after the emergence of kindles, that became less and less appreciated (although some will still accept recommendations).
I pile up books on my desk, on shelves, next to my bed, and it gives me pleasure just looking at them. I hate accumulating physical possesions except books.
I look at my shelf (and my desk, and next to my bed) and it's a monument to things I have had fleeting interests in and things that are life long passions, stories that sits so deep inside me that they have come to define part of who I am, but of course also stories that were mere dreams and left no mark (although I have another pile in a corner for those books that I intend to get rid of... One day).
I love books, it has been the one constant in my life since I was very young child.