fetch_comp.cs

public static class MonoBehaviourEx
{
    public static bool FetchComponent<T>(this MonoBehaviour beh, out T obj) {
        obj = beh.GetComponent<T>();
        return obj != null;
    }
}

// example:

public class Hero : MonoBehaviour
{
    Controller2D controller2D = null;

    void Start() {
        this.FetchComponent(out controller2D);
        // instead of:
        // controller2D = GetComponent<Controller2D>();
    }
}