Anti-Depressant Medication
It's a Wonderful Life is the ultimate in anti-depressant medication. An exceedingly uplifting, heart-warming movie, it will make you smile, cry and it will trigger uncontrollable goosebumps.
The reason why this movie works so well is because it preaches a number of simple, uplifting philosophies. For starters, you NEVER know how much you've effected those around you in a positive way. Also, it conveys the message that you're not a failure if you have friends. If it seems like all is lost, there are still people around you who care about you, who love you, and who'll miss you if you're gone.
What a wonderful movie... If this film was never born, the world would be worse for it.
In the case of Airplane!, this is an instance of anti-depressant medication that just makes me laugh my head off. It does not preach any heart-warming philosophies... Instead, it's a non-stop laugh riot from beginning to end. No lags. No unnecessary fluff. Just laughs.