Plato is mostly dialogues and it is only hard in the sense that I have to extract the philosophy out of the text, plus Socrates goes around and around. Epictetus is ok as well, the text is simple to read, and I found myself taking many notes and comparing his text to others. Modern interpretation of the Quran with commentary is helpful, the thing about it being that each chapter is somewhat separated from the rest. Bible, I picked than put it back down with humility because I just knew I could not grasp it. Aquinas is hard to follow, imo he is a logician before a theologian and I know nothing of the first and very little of the second science. However I am very interested in the subject of his writing. I agree it is "accidentally" mechanical reading although my goal is "understanding." I just started to read heavily the past 2 years and this is my beginner's eagerness.