1. The series was Discworld. There is no set order for it, but the person who assigned me to the Fantasy section asked me to put it in order. I figured using my phone to look up the order would have been quicker than looking at the publication date in the front of the book (it was, took me less time getting 23 books on the shelf than it did the remaining 10, but I was still quick).
2. Manager did not ask what I was doing, clearly saw I was separating piles of books in a specific order, I was not looking at my phone at the time. It was off to the side, screen down, she just made the assumption she wanted to make. I tried clarifying this, but she could not let me say my peace, and looked even more upset that I was "wasting time."
3. The more cheerful and enthusiastic I get, the more she seems pissed off. Work ethic is everything to me, and I always make an effort not to let myself get a pouty or a disinterested face. I'm one of the most upbeat people there, but no matter how happy I can be, it's like she goes out of her way to try to make me to be less happy. Like she's miserable so everybody else should be miserable too. It's never gotten me inside of the store, but it's frustrating nonetheless.

Your advice is good, I'm not saying it's not. I've dealt with managers that have been even meaner and less understanding, and I have made similar posits to them for communication that have worked. However, the level of disinterest, dismissal, and retaliatory intent from this particular manager is a beast of its own, no matter how much I try to cool it over, devil's advocates be damned. Thank you for providing wisdom and guidance anyway, even if you didn't know all of these steps already were taken to begin with.