But it's also really frustrating when you have an itch or if your in an awkward position where breathing is more difficult.
From this, I very much doubt you had an experience of waking up in a sleep paralysis of a meaningful degree. I'm talking about when you realize that you're only awake because you can control your thoughts and receive sensorial inputs (feeling, hearing, etc.) but don't have any movement control whatsoever, not over your breath, not even over your eyelids to open and look around. That in itself, as bad as it sounds, may not be a problem if the awakened mind won't feel the need for more oxygen, yet the breathing stays suffocatingly short and slow for way too long. There's just no out, there's only a wait for some change that will give you back a first bit of motor control.