But is it exercised often is a question of its own. Through your belief in God good will is part of once everyday life. However, in the era of television and sensationalised crime to maintain good will towards other is something very difficult. Despite all the difficulties we face in life if the concept of God grounds you. I believe it is possible but not necessarily seen often.
Yes, goodwill to all mankind is possible. Is it likely? No. Anything is possible. However, as long as people are people there will always be those who are rude and inconsiderate Yes it is sad to say that the prospect of "goodwill to all mankind" is not that likely. However, the silver lining in the cloud is that although it is not that likely, it is still possible, because anything is.
What must first be realized is that the nature of man is not one of good will. People are at their base selfish, and seek their own interests and are not benefactors to others. It is only the manifestation of the Holy in person's lives that generates good will. Only when person's submit to the Holy can good will be possible, and most never do.
You can have a good will towards all man kind. Then someone shoots up a school or a church. It is kind of hard to have good will towards someone who does that. I think that if you go far enough back in a persons life though, you will find something that happened to them. Something terrible that led them to do that terrible thing. And then you can empathize.
Good will to all mankind is possible. It is actually done quite easily. This is done by being a moral and positive person. It is very possible and everyone on this planet has the ability to do it if they chose to do so. Many people have good will to all mankind.