There are many things that you should know in order to prevent yourself from judging people. Don’t judge people by their appearance and never make fun of others. Maybe they can’t buy expensive clothes and lead a luxury lifestyle, but they may do many good things that other people don’t even think about. As I mentioned before, we are all different. Some people can’t afford to buy essential foods, while others spend a fortune on the things they don’t need. Rich people tend to judge poor people, but they don’t know the whole story and they don’t know how poor people help others without expecting anything in return. So never judge someone without knowing the whole story, you may think you understand but you don't.
In short, there are many reasons that will make people act, dress or even talk the way they do. So instead of judging them start understanding.