A phrase said by Kaguya shinomiya from the comic/anime/manga Series Kaguya-sama: Love is War, when your mind goes blank or you don't really have any type of personality or any (normal) tastes you said this
People who live in N.H. or M.E. mostly lumber-jackers, or hill-billies. Mountain beathers can't afford good dental services, and have to drive three hours on dirt roads to get to their destination. Nobody comes to visit them, because nobody can find them, way up high in the mountians. Mountain breathers, are enviormental and ride tractors and go hunting for their food.
Ex: a mountain breather is someone with overalls and suspenders. Someone who doesn't know a thing about political statuses.
One who has had his/her head up his/her (or someone else's) arse for so long that they have adapted to the methane rich atmosphere. See Also: Craniorectal Inversion
The Sales Department is populated entirely by methane breathers. Even if they could pull their heads out of their asses, they would probably die of oxygen overdose. See Also: Cranio-rectal Inversion
John: "Hey Brad I'm gonna go on a date with Janice today but I don't have any gum, mind giving me a Swedish breathmint?"
Brad: "Sure, I ate some Taco Bell not long ago so it's all good."