Explaining bad behavior

Yesterday in my speech class we had to write a journal about attributional patterns and how we explain the disappointing behavior of our friends compared to how we explain the behavior of someone we don’t like.
I personally often dismiss the bad behavior of a friend by saying something like “oh, she is having a bad day or week”. While with someone I dislike I contribute their behavior to them just being mean people. I believe I do this because I want to see the best in my friends. I am the one who picked these people as my friends, if they are mean people then what does that say about me.
When someone I do not really care for does something that is mean, disappointing or cruel than I usually say it is because that person is just a bad/mean person. I think people do this because we want to justify not liking someone. It is a lot easier to not like a person when we actually have a reason to dislike them. It is also a lot easier to say negative things about people we don’t like or even know. For instance, we see someone speeding down the street. Most people just assume they are speeding because they are impatient and have no regard for the safety of others. However, if a friend of ours is speeding somewhere then we are more likely to say something along the lines of “oh, she must have an emergency” or something like that. When it is people we care about we are pretty much willing to make up any excuse possible to make them look good.