I get the "feeling" of a mandela effect far more frequently than i can solidly know for sure. I guess my first experience was decades ago as a child. I recall staring at a Bernstein bears book, and being oddly transfixed by tye fact that the spelling of the title did not match that of the authors name, literally inches apart on the same page. Later i experienced a schrodenbug or two (which i think is the same phenomenon), and one really solid social ME were a church ceased to exist (or got merged into a neighboring church). After the first few, now I fully admit I am WAY too quick to believe odd circumstance is a ME, and usually find myself reluctantly disproving that to myself with notebook/journal entries... only to later wonder how they might change too.