I think we got an answer to what causes abstraction????
"I made a program that creates a body perfectly encapsulating their mind files, and they hate those, too!"
So, if I understand, the shape and appearance of the Avatars is due to a program that reflects the User's mind state. Normally, this program would run during the Avatar's creation and be turned off after it.
BUT!!!! What if the Program is constantly running in the background and it never turns off????
If the "mind files" start to deteriorate or diverge from the original files. Let's say.... Having a complete mental breakdown???
I would assume the program would interpret that mental state as something quite... Abstract????