George, about the possible aggressiveness of the concept of Angst: here we would badly need some intelligent person who has complete knowledge of the German. This interpretation is new to me, but not completely alien if I reflect on it. I think on the painting of the norwegian artist Edward Munch. His famous painting "The Cry" has an air of aggression, but it is also an expression of a most intensive suffering, Angst. Usually suffering tends to elicit aggression afterwards. One of the milder forms is lying, especially when a client wants to lie to the professional person or educator, and thus humiliate him/her.
Trevor: about existentialism. There is an element of existentialist philosophy in Adlerian psychology, if I have understood correctly what I have studied. Adler says that we have the freedom to choice, but also the responsibility in our choices. There is nothing that "determines" our choices. This a task of life that we must perform ourselves. This duty may sometimes elicit Angst (or anxiety?).