A person is being rude when he violates your personal space. Rudeness is when a person goes beyond your boundaries and disregards your feelings. Or it is when a person makes fun of you beyond your tolerance level. A person is considered rude when he makes you uncomfortable, unnerved, and awkward.
When you are forced to deal with this kind of person, you often end up annoyed and irritated. If you hate the guts of a particular officemate, a classmate, a boss or a professor, you develop a dark aura. You hate seeing him because he constantly makes fun of your clothes, or he deliberately finds flaws in your work. Irritation builds up to resentment as rude behavior directed at you piles up. Your overall attitude is affected. You tend to snap at other people, and you easily get upset.
How do you deal with him?
Express your concern. It is the easiest thing to do, but it is the most often neglected. Don't you envy children who unguardedly speak their minds about almost anything under the sun? If you are uncomfortable, tell him straight out. Tell him your feelings in a calm and civil manner. It is the obvious thing to do. Do not keep your anxiety. The person might think that what he does is okay with you. You will never get the message across when you do not apply the first step.
Worst case scenario, he does not take your words seriously. Despite your concerns over his actions, he continues to berate you or find fault in you. Take control. A deliberately rude person wants to control and dominate you. Respond to his antics as calmly as possible. If you lose it, he wins. You give him the satisfaction of provoking you to retaliate.
Ignore. If rudeness comes from a stranger or a common acquaintance, just let it pass. It is not worth your time and energy. Wish him well, because the next time around he might meet his match and reap twice what he has sown. If rude behavior comes from an officemate, a boss, or a neighbor, let them think that you cease to be affected. If you have tried steps 1 and 2, and he still continues to be rude to you, ignore him. If he feels that his offenses do not accomplish its purpose, he will eventually grow tired of it. Think of a child who does everything to get what he wants. If he observes that his antics does not get you to do what he wants, he will eventually tire out.
Always maintain a happy and confident disposition. If you are sure of yourself, and you maintain a generally happy disposition, you will not let other people's opinion affect you. You know yourself, and you know that you are special despite your limitations. People who have ugly things to say to others carry grave insecurity within. They berate someone because it makes them feel that they are better than other people are. They lack self-confidence and are commonly unhappy in their lives.
Lastly, you do not want to live the rest of your days forcibly trying to keep a good mood while anxiously waiting for the next round of attacks. Consciously deal with it. It is easy to say but difficult to do. It will take a lot of strength on your part to finally put a stop to a person's rude behavior towards you. As you continually hold a grudge over the rudeness of a person, you may act on impulse one day and regret your actions. Also, be conscious of your own behavior. It is indeed true to say, "do unto others as you would have done unto you." - Golden Rule