We've all done it or been tempted to. Sometimes it feels like if two people agree about a wrong someone else does or did it brings us closer together, somehow bonding us. This is a weakness, this is our weaker self being seduced by the shaitan. Please sisters beware of this do not justify it because you really are convinced this person's actions are bad. Even if you think a thing inside your head, do not spread it. Maybe you will get over what you initially judged on a person but maybe the person you told will continue to judge the other. Now you have done more than one wrong.  I am very aware of the weakness I have inside myself. Many times without wanting to I meet someone and think a bad thought, see an action of a friend/acquaintance and think I don't want to really be a close friend to this person.  Our thoughts sometimes are hard to control, but our actions we can control. I choose not to spread these thoughts I have about others for many reasons. One I could be mistaken, could of read the person wrong, two, this person could be having a bad day- and misrepresent herself, Three- this person cold benefit my faith myself and by spreading rumors or bad info about her I could push her away from me and my friends, Four- God made all people so it is better to try and subtly help this lady even if she is wrong rather than only focus on her mistake, the list goes on and on. 
Try giving the person excuses. For example:
Try These  Excuses
  • He was having a bad day.
  • It was a misunderstanding.
  • She didn't hear me.
  • He tried.
  • She didn't have time.
  • He had no other choice.
  • She didn't mean it.
  • He's upset about something else.
  • It was an accident.
  • He's having problems at work.
  • She had an emergency.
  • He's not feeling well today.
  • She was in a hurry.
  • He didn't know.
  • She got lost.
  • He didn't sleep well.
  • The car broke down.
  • She didn't realize.