The first time I smelled Brett(anomyces) in a beer, I instantly thought about my long-passed grandmother. That surprised me. She didn't drink beer, at least not around me, and certainly not barrel aged beers.
I dug into that memory a little deeper - what specifically about her was I thinking about? And I realized it was her basement. She had a very old house and even older cellar, the kind that really put the "root" in "root cellar" - stone walls and dirt floors. I never spent much time in the basement as it spooked me out as a kid, but that musty smell of wet earth and stone stuck with me, buried deep in my subconscious to be resurrected by a beer of all things.
Some people get "barnyard" or "horse blanket" from Brett. Having spent a considerable amount of time growing up in barnyards and around horses, I can't say I understand the connection. But damp basement, Brett has that in spades.
A flavor and aroma descriptor used to describe beer an awful lot (image source)
Am I wrong for linking Brett to basements instead of the textbook descriptors of farms? Absolutely not. Studies have shown that your sense of smell is one of, if not the, strongest sensory link to memories. It makes sense given just how close your nose is to your brain.
It's easy to fall into the trap of thinking about what you should be smelling or tasting and letting that get in the way of what you're actually smelling or tasting. If a beer smells like stale Cheerios or a candy from your childhood (or even cat urine) - don't ignore it, but rather lean into it and see if you can find the source. A beer that smells of circus peanuts and strawberry starburst is way more interesting than vaguely saying a beer is "fruity". Trust your instincts. The nose knows.