You are correct! I missed 4...Qg7! Thanks for keeping me on my toes! I will go to the nearest QA (Queen-sacker's Anonymous) meeting for one week as punishment!

Well as my "Pappy" used to say (when I was just a little 'stabber) "You gotta lose a fly to catch a trout." And he didn't even fish. Anyway, in chess terms that means that we are always trading one advantage in for another: a bigger and better one, or longer lasting. This is really all a sacrifice is, you trade one element (force) for something that is worth more than the material sacrificed. Often a sacrifice is the fastest way to win....look at the games of Kasparov, Shirov, Polgar....their games are filled with sacrifices. And yes, if your "sac" doesn't work out, you may lose, but it's not fair to attribute this just to sacrifices---make enough bad moves of ANY type and you will lose.

Opposite colored bishops have a few significant features to them. By definition, it is where you have (for example) a white-squared bishop, while your opponent has one which is on the dark squares. In the endgame this means an increase in drawing possibilities, despite being other material down. Look at the diagram. White draws because of the opposite colored bishops and black cant destroy the blockade. In the middlegame, opposite colored bishops can favor the attacking side.....especially if there is a weak square complex that is the same color of the attacker.