Ever okay to allow a fork?

After game against the 1200 cat computer, the game review said one of the best moves was moving a knight on the same rank as a bishop allowing a fork. Is that ever good to do?

Yea I get that, that makes sense. In this game, I just sat there for a few trying to figure out if there some majestic moves after the fork were to happen. Looking now, Ng6 attacking the rook, rook moves then could move the bishop to safety. 

Totally. I have an example in a game I played (I had the white pieces)

Black resigned here. Maybe this example is more obvious but of course if black forks and takes the rook then they just lose it back with check and white is completely winning.