basically a phrase instead of "oh my gosh" etc. it's rather fun to say, and it sounds cool. besides, if something astounds you, your head is busy thinking so it makes sense
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.