Bildungsroman stories are coming of age narratives where the personal growth of the protagonist is the main plot point; 19th century examples would be Great Expectations and Jane Eyre. Personal growth means learning and accepting new ideas … which can be very hard, even for a teenager. Most growth is painful in some form or another, as most lessons are learnt from making mistakes.
Old ideas and values are corsets, holding a straight-laced character rigidly in place. While giving support to a character, they also restrict their viewpoint. Cutting the laces gives the character freedom, but it also means that they have to grow a backbone.