Quality suggests the best that we can be. Poor quality means we are falling below our own spiritual aspirations. Good quality being highlighted in a dream can suggest some hidden approval.
Psychological / emotional perspective: When quality is an issue in dreams we are perhaps not certain that we have put our best efforts into what we are doing. Emotion may be getting in the way.
Material aspects: When we find ourselves in dreams dividing things into separate groupings – for instance into good and bad, or best and worst – we are questioning our own ability to differentiate.