Modern chess and its guidelines!

There is a lot of guidelines in chess, telling us things like "A knight on the rim is dim".
But sometimes we need to think outside the box and not follow guidelines:

"…modern players will often neglect development for structure, allow backward pawns in the opening, move pawns in front of their king, attack the front of a pawnchain, and advance flank pawns when the central situation is unresolved.

On the other hand, they will just as often do the traditional thing (develop quickly, avoid backward pawns, keep kingside pawns on their original squares, etc.).   

We found that bad bishops are often not bad at all, that knights can be strong on the edge of the board, and worst of all, that the knight-pair can be superior to the bishop-pair in either very closed, semi-closed, or wide-open positions! You can successfully grab flank pawns in the opening with your queen when you're staggeringly behind in development; or you can do so and quickly be mated. And so forth when it comes to exchange sacrifices, prophylaxis, etc."     
– John Watson, Secrets of Modern Chess Strategy