In the United States there is a cultural idea born in part by early commentators, like Ralph Waldo Emerson, on the Bhagavad Gita and the Buddhist Sutras that meditation is about control, that this control requires one’s own individual efforts alone, and one will eventually experience peace if practiced for long enough. These ideas are fine but can be misleading when taken out of context.
Sometimes people make the mistake of thinking meditation is going to do something for them, make them calmer or happier. There has been loads of research on how meditation does that. But without adequate preparation it really just gets us in touch with our own misery. This is why I suggest asking not what your meditation practice can do for you, but what you can do for your meditation practice.
A prejudice mind is one that is experiencing fluctuations. It is the opposite of steady. When our mind is not steady, we know we are not seeing reality as it is. But this insight into our fluctuating mind only comes if we have a practice well established. Otherwise, we filter what we perceive through our confused senses as reality. We think what we are seeing is real, when in fact we are mistaking a distortion for reality.