Most Tai Chi Chuan players are fast to claim they know the form they are doing when asked. They will tell you it is 24 postures, 48, 36, 108 and so on. Nothing wrong with that, and when you ask them to show you the applications of these postures, many long time practitioners will be able show you how a posture can be applied to intercept an attack, often in a stationary manner. Often a ward-off posture is used to deflect a straight jab or punch. Try probe further by asking them how a ward-off can be used against a rain of multiple punches. I can guarantee you many would struggle to give you a satisfactory answer. Why? It is because ward-off cannot be used to defend against multiple punches, not in the way it is often demonstrated. If you are careful to scrutinize Tai Chi classics, it advises us never to oppose force with force, never to confront an opponent directly from front.
So what is missing? Most Tai Chi Chuan people lost touch of the transition movements in the form. Transition movements link individual posture together and they are very very important. It is here that hides the secret stepping application of Tai Chi Chuan. It is here that side stepping, gaze to the left, beware of the right, retreat and advance are hidden.