An irritator's guide

The Cambridge dictionary describes irritation as "something that annoys you or makes you angry". When you annoy someone, you are accused of irritating them or of being an irritation to them. For all those who take a particular fascination in irritating others, you should meet my sister. She has a PhD in irritation. As for those others who just want to aggravate someone else as a part of sweet sweet revenge, all aboard! You will be provided with a detailed guide that contains some pretty useful tips that are going to equip you in your journey towards a better future in the art of irritation. 
The first step is to find someone to irritate. This is extremely easy to do. For the most dynamic results, you might want to aim for middle aged or older folks who are preferably doing something very serious at the time of your attack. (Please take note that trying this with your parents might lead to very horrible results. For the least damage, make sure your health is properly insured.) If, by any chance, the person unfortunate enough to be your victim is neither middle aged nor serious, it does not create a considerably huge alteration to the below mentioned methods. 
Consider the case in which the victim is your poor, unsuspecting mother. The ideal time for your strike would be when she is cooking- preferably in the early hours of day when her rush is elevated to that of the rush hour in Mumbai city. Start by asking something so trivial and insignificant and work your way up till you notice a hint of annoyance appear on her lovely face. This is the signal for you to spike up your game. Nagging and whining might catalyze this process and produce much more results at a much faster rate. Then, exactly when she is about to break, cry out "MAMMA" and flee for your life.
In case your victim is your father, I take a moment to advise you to stop right there. Fathers are more skilled in being annoyed and their patience threshold is easily overcome. Their motor senses are also much more enhanced, which means you will not see the slap until after you feel the pain of all five fingers slamming into your cheekbones. 
Your sibling is an ideal choice for a victim. Frankly speaking, I think this is the only use they possibly can have. It is surprisingly easy to irritate one's sibling. A simple pinch or a scratch will do. In fact, a mere cutting remark is enough to send her into peals of anger, her long arms flailing around, reaching to pull at your hair while punching in your gut at the same time, defying all the laws of  martial arts. Your sibling will turn into a mini ninja within a matter of seconds and you will have successfully provoked a malicious, hypersensitive monster.
If you wish to make a sitting target out of your friends, you might have to think a lot more. Depending on how close you are with your friends and how long you have maintained their acquaintance, they might as well be planning a similar prank on you. Tread carefully on such grounds.
Targeting your best friend is easy. Their likes and dislikes are pretty evident. Intermixing the two extremes will help your cause to a great extent. For example, mine loves food and hates lizards and geckos. Hence, an ideal way to irritate her would be to tell her about the time a lizard jumped on my head and ran across my face while she eats her lunch. This will result in her gagging up her half chewed food and screaming at me in frustration. As the sense of fulfilment washes over me, I will feel like I have done something worthwhile with my life.
If you are a person who wants to annoy both your parents in one go (in that case you probably have a death wish), then look no further. There are many ways to annoy your folks, some of which include showing them your report card, telling them they are wrong about something, asking them a lot of questions (like why a building is called a build-ing if it is already built), watching them break something by accident and viciously smiling at them, waking them up at four on a fine Sunday morning, eating the last cream biscuit, coloring outside the lines, asking your grandparents about how they were when they were young, the list is endless.
The art of irritation is one that is successfully passed on from generation to generation, thereby rearing a troublesome, more irritative society, whose primary goal is to annoy others. Look around you and you will witness many people who have made it a hobby to be on everybody's kill list. My blessings lay with your soul and soon-to-be-punctured face. All the while, take care to remember - There are a 100 billions nerves in the human body, and you have the potential to irritate all of them. So never give up.