Nothing, if you like killing ideas and spoiling morale. There's a better way ...
Instead of picking apart, try putting together. Instead of being an devil's advocate, try being an angel advocate! Rather than seeing all that might be wrong, try seeing all that might be right. Build rather than plunder. Construct rather than destroy. With a positive approach, you can repair and heal, strengthen weaknesses, counteract threats, build on strengths, and capitalize on opportunities that might otherwise be lost.