Brain shutdown is a thing. And now I know how it happens (though I may not necessarily be able to describe it in words that are apt, because it's more or less an elusive idea - not tangible.) It doesn't happen because of a guy. Or a girl for that matter. Intimidation, however, could be a chief cause.
When someone throws words at you that reek of eloquence designed specifically in twists to make you feel inferior Or when you come across terms that are alien, important and alien, like Physics or Philosophy, Maths, or anything else really that is "important" to get and you're all pressured, and alien, Existence Of God - Nonexistence of The World.
Or when it gets too much from people and circumstances And you feel like you're standing mid-road with all that traffic coming to hit you on your face so you will fall, so you will disappear And instead, your mind falls. and it disappears. and quitens entrapped in a blanket, this brain of yours you go whoosh. BLANK.