Dominating and giving someone (e.g. a child) no choice; crushing their freedom and constantly limiting them: "Don't do this!", "Don't do that!", "What are you doing?!" (the last one said sarcastically, demeaningly) etc.
Lines (directions of willfullness) cannot be obstructed. They must be allowed to express themselves freely. To continually obstruct them or somehow prevent them from expressing themselves will give rise to apathy, despair and other simliar feelings. Why? Because the line has no freedom (unrestrained horizons) or hope (possibility of expressing its will as best as it can). In turn this can lead to what are called 'psychological disorders' such as schizophrenia, schizotypal and to a lesser extent schizoid behaviour. All of these are gradations or variations of a basic theme: disconnection by the persons mind/psyche from the physical world because it is so oppressive and freedom denying. Schizoids often have a higher degree of introversion (detachment from the physical world) yet can still interact with it to a greater extent than true schizophrenics, which means that they can produce works that have a perspective on the world that other (low - non schizoidal) people would/do not have. Just think of it in terms of a man who can stand in one of two places: either on the mountaintop, observing the entire stretch of a river below him, but unable to interact with it; or in a kayak on the river itself, but with a perspective that is limited to a hundred metres fore and aft of the kayak. In short: observation of the world, or interaction in the world.
Generally, obstructions to someones willfullness effect undeveloped, fragile people more harshly/easily than those who are more robust (either as a result of their character, or their maturity). Therefore should be treated more gently than you otherwise would be. For instance, telling a sensitive child "Don't do that!" is going to have more of an impact/impression on their character than saying "Don't do that!" to a veteran of the army for example.
As well as applying this to people with a sensitive disposition, it also applies to more robust people who may be in a sensitive state following a traumatic experience. For instance, a driver who has just been involved in a serious road traffic accident (RTA) for the first time, they will be more sensitive to external stimulus than if they had not been in an RTA. This means that they would be less able to deal with complex stimulus (either physical or mental) than they otherwise would be. Consequently when dealing with someone in this position, they should be treated gently, and with simple and low frequency stimulants i.e. basic vocabulary over complex vocabulary, a few questions over many questions, simple foods over multi flavour foods, few people over many people, simple colours (uniforms) over complex (multicoloured or patterened) ones. In addition to keeping the complexity and frequency of external stimulants, the element of time should be considered. Thus slower changes over quicker ones (e.g. the period of exchange when handing a trauma patient/sufferer from one doctor/paramedic to the next), experiences that are longer lasting over ones that are rapid (e.g. bodily movements).
Furthermore, in addition to interacting with people who have suffered trauma, it may also be applicable in normal, everyday situations, for instance meeting/interacting with a nervous individual (who may be smiling excessively almost compulsively, see my article on 'Laughing'), or giving someone a discouraging (mildly traumatic) piece of news.