My hobby is going to expensive restaurants, ordering their popovers, and leaving them leaving a note with the bill, just to let them know that if they warm the milk before they mix in the rest of the ingredients, it might actually work.
Basic models of flocking behavior are controlled by three simple rules: 1) separation: avoid crowding neighbours (short range repulsion); 2) alignment: steer towards average heading of neighbors; 3) cohesion: steer towards average position of neighbors (long range attraction). With these three simple rules, the flock moves in an extremely realistic way.