Some people on spiritual path believe that we should consider every one good and nice to progress spiritually. So they simply deny that some one is selfish or behaved wrongly. Many times, these people say that we should not be 'negative' on the spiritual path and consider everything well and good.
Though there is some good reason in this kind of attitude, I don't agree with this opinion. When we are in the beginning of the spiritual path, if we keep this attitude and refuse to see 'bad' anywhere, we may fail to protect ourselves or avoid wrong people.
The fact is every one is a soul and originally every one is God. But this does not mean that we justify any and every action of everyone (including us). This is because most of us are not acting from God consciousness.
Swami Sri Yukteswar said - keep the good company and avoid bad. He defined good company as people whose magnetism affects us harmoniously, who cool our system, internally invigorate our vitality, develop our natural love, and thus relieve us of our miseries and administer peace to us.
It is clear that if we don't notice the 'bad' we can not discriminate between good and and bad. So it is important for us to understand what and whose company is not good for us in order to avoid it.
However it is important (a) not to be judgmental (b) not to elaborate too much on negative things and people (c) not to maintain any superiority based on our perceptions.
The real understanding of good and bad comes out of intuition when the mind calms down. It is said that in the presence of self realized masters even cruel animals act with love. This is because of their higher consciousness and their ability to influence the sorroundings. Such people truly can say everything and every one is good and indeed that is our highest goal.