It feels weird to say but I hate them. I don't know if I Would describe them as painful, but they're definitely uncomfortable. It does not feel right in my chest or my throat. And I hate how irregular the rate at which I inhale/exhale air is when I try to do it slowly. And I can't breathe in/out for as long as I've been instructed to. Ok when I write all that out it kind of sounds like I have a medical problem. But to my knowledge my breathing is fine I passed the test with that thing doctors wear around their neck the stegosaur or whatevr