I remember my disgust when I saw a package of Oreo cookies on a friend's altar. So disrespectful, I thought. In short, I was obsessed with the external details and formalities of my practice. Some of this stuff was good in essence. I developed my ability to concentrate intensely through chanting.
Buddhist practice is really about opening up.
Theravada Buddhism is strict and literal about following rules that are stated in the sutras. The sutras are sacred scriptures, the words of the Buddha Shakyamuni. There are thousands of sutras and some of them seem to contradict one another. At any rate, Theravada has an ascetic, monastic flavor. A problem with this is that you don't necessarily have to care about other people, since your focus is your own enlightenment.