what is considered bad??

Today during dinner I got into the discussion 'what makes someone a bad person'? with my parents. My parents started listing examples of their friend's kids saying they are bad because of such and such. Having known the people they were talking about myself I tried to defend them because I personally they are not really bad! One example they said this kid is bad because he lies to he's parents that he is going to tutor, but instead he uses the money that the parents gave the kid to tutor for other purposes. Then I was like...right, thats considered bad in your books? I just don't understand why that is bad. Well to some extent it is because you are stealing from your parent. But come on, who hasn't stole from their parents and lied to them? I can say I have. I remember I stole coins from the car to buy snacks when I was primary school. Prob because all the other kids have canteen snacks except for me. They don't know what other 'factors' out there that makes a bad person. So I started listing things like the kid takes drugs, having one-night stands and kills people. And my parents said, well those are extreme cases and if that happened to us we won't even consider the kid actually related to us at all. We will pretend that we never had that kid before. How loving is that? But what I was disgusted about them the most is that they talk about other people's kids and how bad their are without thinking whether there is another side to the story. Because all they are hearing are just the parents side and sometimes adults can exaggerate! *sigh* parents... they always think they are right. And when I try to tell them my point of view they stop me, and say no no no, that is not right, because I am right. Its probably because they listen to too much chinese radio and reading too many of those chinese books...