Joseph Henry Blackburne said "Never start an attack until your queen's rook is developed." Garry Kasparov said "Chess is all about piece activity." Other have said “In the opening, move every piece once before you move any piece twice, unless there is a tactic.” “A premature attack is doomed to failure.” “If you don’t know what to do, identify your worst piece and make it better.” “In the endgame the most important idea is often to activate your king.”