I can't read just 1 book at a time. A lot of times I am really enjoying a book, but I'm just not in the mood for it, but I still want to read. Sometimes I get really bad book anxiety and I need to put the book in the freezer for awhile. (metaphorically à la Joey on Friends)

Not to mention that certain books (Non-fiction or classics) I prefer to read in small doses, whereas other books I read them straight through.

Sometimes I even do this thing I call Round Robin where I read a few chapters from each book that I am currently reading in a row, and when I finish I circle back around and start over.

I realize that this might not work for everyone, but I find it very freeing.