This is something that I have been thinking about a lot lately. When I was younger sketchbooks terrified me! I would buy a hard-bound book simply because I have always thought spiral bound ones look and feel cheap (in all honesty it doesn't matter, it's just a preference). The difficult part about liking a hard-bound sketchbook was that I couldn't tear out the pages when I did a bad drawing. If I did there would be evidence. That fear kept me from doing very much sketching.
Years later I still struggle a little with that fear. I am also happy to say that I'm getting better. None of us will ever be able to do our best and most creative work if we are too afraid to make a bad drawing. So I'm still working to get over it, and not care so much what anyone thinks. It's really quite liberating when I do break free.
Ryan Woodward recommended a book to us last semester called
An Illustrated Life. It includes sketchbook pages from different artists and designers, along with their personal thoughts on sketchbooks. I usually read one entry a day. I highly recommend checking it out.