MonoBehavior.cs

using UnityEngine;

public abstract class MonoBehavior : MonoBehaviour {
    // private cached variables
    private GameObject _gameObject;
    private Transform _transform;
    private Rigidbody _rigidbody;
    private Renderer _renderer;
    private Animation _animation;
    private Animator _animator;
    private AudioSource _audio;
    private Collider _collider;
    private Camera _camera;
    private Light _light;
    private Rigidbody2D _rigidbody2D;
    private Collider2D _collider2D;

    #region public getter properties
    public new GameObject gameObject {
        get {
            if (_gameObject == null) {
                _gameObject = base.gameObject;
            }

            return _gameObject;
        }
    }
    public new Transform transform {
        get {
            if (_transform == null) {
                _transform = base.transform;
            }

            return _transform;
        }
    }
    public new Rigidbody rigidbody {
        get {
            if (_rigidbody == null) {
                // get the attached rigidbody if one exists
                _rigidbody = GetComponent<Rigidbody>();
                if (_rigidbody == null && collider != null) {
                    _rigidbody = collider.attachedRigidbody;
                }
            }

            return _rigidbody;
        }
    }
    public new Renderer renderer {
        get {
            if (_renderer == null) {
                _renderer = GetComponent<Renderer>();
            }

            return _renderer;
        }
    }
    public new Animation animation {
        get {
            if (_animation == null) {
                _animation = GetComponent<Animation>();
            }

            return _animation;
        }
    }
    public Animator animator {
        get {
            if (_animator == null) {
                _animator = GetComponent<Animator>();
            }

            return _animator;
        }
    }
    public new AudioSource audio {
        get {
            if (_audio == null) {
                _audio = GetComponent<AudioSource>();
            }

            return _audio;
        }
    }
    public new Collider collider {
        get {
            if (_collider == null) {
                _collider = GetComponent<Collider>();
            }

            return _collider;
        }
    }
    public new Camera camera {
        get {
            if (_camera == null) {
                _camera = GetComponent<Camera>();
            }

            return _camera;
        }
    }
    public new Light light {
        get {
            if (_light == null) {
                _light = GetComponent<Light>();
            }

            return _light;
        }
    }
    public new Rigidbody2D rigidbody2D {
        get {
            if (_rigidbody2D == null) {
                // get the attached rigidbody if one exists
                _rigidbody2D = GetComponent<Rigidbody2D>();
                if (_rigidbody2D == null && collider2D != null) {
                    _rigidbody2D = collider2D.attachedRigidbody;
                }
            }

            return _rigidbody2D;
        }
    }
    public new Collider2D collider2D {
        get {
            if (_collider2D == null) {
                _collider2D = GetComponent<Collider2D>();
            }

            return _collider2D;
        }
    }
    #endregion //public getter properties

    #region Typesafe instantiation
#if UNITY_3 || UNITY_4
    // Unity 5 includes this now.
    public static T Instantiate<T>(T obj) where T : Component {
        return (T)Object.Instantiate(obj);
    }
#endif

    public static T Instantiate<T>(T obj, Vector3 position, Quaternion rotation) where T : Component {
        return (T)Object.Instantiate(obj, position, rotation);
    }

    public static GameObject Instantiate(GameObject obj) {
        return (GameObject)Object.Instantiate(obj);
    }

    public static GameObject Instantiate(GameObject obj, Vector3 position, Quaternion rotation) {
        return (GameObject)Object.Instantiate(obj, position, rotation);
    }
    #endregion //Typesafe instantiation
}