Book worm?

There is this guy I am in good terms with. Next, I make a couple of mistakes and things turn sour. First, I borrow one of his books to read - Michael Moore's Stupid White Men. A few days before, I borrowed a book from the library - Michael Moore's Dude, Where's My Country. About a month later, this guy comes to my room to pick up his book. Instead, he takes my book by mistake, which I do not realise till today, when I have to return the book I borrowed. That's the only Michael Moore book in my now almost empty room. When I realised he took the wrong book by mistake, I take it personally to him to get it exchanged. That was the second mistake - taking it to his room instead of just sending an email. When I go there, he is not in his room, so I wait. Looks like he is having his lunch. After some 20 minutes, his neighbour spots him chatting out in the mess. Even when called, he doesn't come up. OK, his prerorgative. Like an idiot, I leave the book in his room and go down to call him. After pushing him for about 20 minutes, he comes up finally. I tell him that he took the wrong book by mistake. We go to his room and he sees the book I took to his room sitting on the desk. He says that was the book he took earlier. I try to reason with him that was the book I brought just now and tell him to search for my book. He adamantly refuses to listen to me and insists that he took only one book and this was that book. I repeatedly ask him whether he took a book, for which he answers affirmatively. When I try to reason with him that he took the wrong book, he refuses to even consider the possibility that the books might have got exchanged. He then accuses me of losing the book and trying to place the blame on him.

What is it with me that makes me do business with only such guys? If he did take the book and what the hell was the book sitting on my desk for a week? What is the book that I took to his room? Why was I such an idiot to take the book back in the first place? The trust I had in his reason?