It’s not so much understanding or even intuition that quantum mechanics defies, but our sense of logic itself. Sure, it’s hard to intuit what it means for objects to travel along two paths at once, or to have their properties partly situated some place other than the object itself, and so on. But these are just attempts to express in everyday words a state of affairs that defeats the capabilities of language. Our language is designed to reflect the logic we’re familiar with, but that logic won’t work for quantum mechanics.