There are a lot of brutal drivers on my commute. But I think, it´s not normal if people are cutting you off in traffic and putting others in danger.
There are a lot of rude tenants in the building. But I think, it´s not normal to slam doors, to walk down the stairs yelling and dump waist anywhere.
There are a lot of mean coworkers at my job. But I think, it´s not normal if colleges are sobbing hysterically because they have been humiliated.
If you sum up all these scenarios, you can easily come to the conclusion that human beings are aggressive – in general. You can get the impression, that it is normal for people to be brutal, rude and mean. Hopefully that´s not true. Because if aggression is the norm, at some point you will be confused by a person smiling at you. Soon, you will be weird out by a friendly encounter.