Have you ever wanted to wash your lungs with liquid oxygen?
@femme not enough? It must be pretty cold to get liquid, around -182°C according to wikipedia. It'd insta-freeze a big part of your body, starting with anything that gets near the oxygen.
Also, if you tried to breath pure oxygen, you would get poisoned, oxygen is actually pretty dangerous when not in the same proportions than in our atmosphere.
(Sorry to break in with science)