This may seem like a child's question, but it's one I never thought to ask as a child, so I never learned the answer.
Rabbinic traditions — even within continuous geographical lineages amongst ashkenazim, sefardim, mizrahim and the rest — are full of disagreements about all kinds of halakhic practices, all of which are represented by individual rabbis who presumably lived by their teachings and thus practiced differently from one another. Surely all Jews have their beliefs about which practices are “right” and which are “wrong”, but these differences are still a celebrated part of our greater tradition, and it’s not as though the rabbis with minority or overruled practices are rejected from the religion. So since the rabbis are all still rabbis, how could any of their particular practices be “wrong” in the eyes of Hashem?
I think this is a separate question from the halakhic questions of what contemporary Jews should or shouldn’t do — we’d tell them to consult their rabbis with those questions. But theologically speaking, how should we understand the holiness of the practices of the rabbis whose practices differed?
Edit to explain difference from this question: The question "how can eilu v'eilu be consistent with absolute truth?" seems more philosophical and less personal than what I'm asking, and thus I wasn't quite satisfied by the answers posted there. What I'm getting at is, how can we relate to all the diverse teachers and examples in our tradition without being worried or upset about them, given their different ways of practicing?