Simple luck makes for the best feeling sometimes.
Down 30 HP to 14, my opponent plays Rag into a board that has a few other creatures.
I've got a few creatures myself, including a Divine Shielded Sunwalker - but I've 0 cards in hand.
My opponent trades his units for mine, while breaking my Divine Shield on Sunwalker. Rag hits face. I'm now down to 6 HP.
On my turn, I draw a second Sunwalker and play him. I hold my first one to increase board presence against Rag.
On my opponents turn, he plays out a bunch of minions, setting up to end the game (unless Rag hits face again, and it's irrelevant).
Rag shoots my new pretty Sunwalker, eating his Divine Shield, but killing nothing.
I draw Kel'Thuzad.
One play later, and a dead Rag removed from the board, I've got two fresh Sunwalkers with two fresh Divine Shields.
The game was more or less over at that point. My drawing my own Rag the following turn was just salt on the wound.
Credit my opponent for not conceding and playing it through.