Hi Walter,
I, too, used "Rita's book" when studying and I took the practice tests from the book. I do not recall them having been "tricky" in the sense of intentionally misleading. However, the PMP exam questions do require a solid understanding of the terms and usage as laid out in the PMBoK and as presented in the training materials (e.g., PM PrepCast, etc.). As Cornelius states time and again, one must learn to read the questions quite carefully in order to assure clear understanding before attempting to answer. This includes questions that, at times, present some superfluous information that is best ignored when answering - which, I suppose, is sort of "tricky" while still not being unfair. After all, a PM has to wade through droves of irrelevant information on a daily basis.
When I first started studying, I quickly found that most of the time when I missed a question it was because I didn't read thoroughly and then pause to think a moment. I had to make a concerted effort to slow myself down a bit and engage my brain. For others that I got wrong, I delved into the answer to make sure that I understood WHY the correct answers was, indeed, correct.
I would encourage you to really dig into the questions you thought were tricky and see if you can tease out the reason that it seemed so to you. It may help you in progressing in your studies.
Best of luck!
Tracy