To illustrate the point clearly, imagine one morning you woke up with a foggy mind and vague visual of the day ahead. Isnt it that the world around you also appears to be dark and foggy, too? On the other hand, when the world seems beautiful and light one day, you should understand that basically, those impressions are coming from your own mind, rather than from changes in the external environment. Therefore, instead of misinterpreting whatever you experience in life through judgmental wrong conceptions, you should realize that it's not outer reality but only mind.
For example, when everybody in a classroom looks at a single object, say, the teacher, each of the students has a particularly different notion on him, even though, simultaneously, they are all looking at the same thing, or person for that matter. These different experiences don't come from the teacher. They come from the students minds. Although they all see the same face, the same body, and the same clothes, their interpretations are still superficial. Analyzing deeply, the way they perceive him and the way they feel about him, is individual and different all of which came from the mind of the students and not from the physical manifestation of the teacher.