If someone is a strict Rationalist, and does not believe in many forms of Jewish mysticism, how does one go about avoiding it? I ask because kabbalistic mysticism has infiltrated many halakhoth and practices without a clear distinction of what's going on.
An example would be Qiddush. Originally Qiddush began with "וַיְכֻלּוּ" but due to kabbalistic ideas of word numerology, the words "יוֹם הַשִּׁשִּׁי" were added. Because there are halakhoth that say you can't say a partial verse, certain Rabbis/Communities also added "וַיְהִי עֶרֶב וַיְהִי בֹקֶר " to make it so that you are saying a complete verse. So when you open up a siddur, there are many variations of Qiddush, but none of them retain the original begining with וַיְכֻלּוּ, they also make no mention of why the additions are there, or their history.
So when mysticism that one may severely disagree with has embedded itself so deeply in the tradition that one can't just open a siddur or a book and distinguish it, how does one go about building a life free of mysticism?