Totally and completely surprising, with the sense that whatever is described as such is shocking enough to change one's view of the world. However, the phrase is often used hyperbolically. Finding out that my dad isn't my biological father has been completely world shattering. I don't know who to trust anymore. A: "Oh my God, did you hear the world shattering news?" B: "Yeah, I can't believe that Sue is leaving the company. It won't be the same without her!"

To undercut one's dreams or optimistic views. I became a lawyer after my parents dashed my hopes of being an artist.

Not surprising. Greg has been staying late at the office regularly for months, so it's hardly earth-shattering news that he was chosen for the big promotion.

To undercut one's dreams or optimistic views. I became a lawyer after my parents shattered my hopes of being an artist.