For me, books for self-studying should have a slightly informal tone and ramble a little. The book is your teacher, and I'd like my teacher to speak to me as a student, not a theorem prover, as least when I'm starting. Spivak, Pugh and Axler are some good examples, while I could only grok Rudin after learning all the basic.
Not a lot of experience with physics but I like Symon's Classical Mechanics and Purcell for the same reason. Kleppner's mechanics book has very good exercises too.