Sometimes a sense of selfishness and inability to forgive makes you hurt and hurt a person. It is not difficult to cause human suffering, the main thing is to understand why it should be done.
If your goal is to hurt someone, be careful not to take it to the extreme. Most of the suicides are carried out by men, and often they do it because of poor relationships. Therefore, in the desire to take revenge, keep within reasonable limits.
It is best to inflict minor offenses. For example, make fun of his physique, give him a book like How to Build Muscles. Parody his manner of speech. If you wish, you can find many minor flaws. Any bright qualities can be interpreted as flaws. Generous means badly with money, kind means weak, cheerful means not being able to really look at life. These are all minor flaws, but repeating them often enough can make the guy suffer.
If you want to seriously offend, then you need to touch pride. His creative experiences should be ridiculed, his achievements should be declared mediocre, and his ability to build relationships should be subjected to ruthless criticism. The most effective way to hurt is to criticize a guy's sexual performance. This is the most vulnerable area for many young men. If you decide to end a relationship with him, tell him that other women are simply insincere in praise, because they want to get something from him. This, of course, is not easy to prove, but the thought itself will constantly revolve in the subconscious of a person and poison his intimacy with other girls. After all, it is quite easy for a woman to simulate pleasure. So let him ponder whether he is such a hero-lover as he used to imagine himself.
If you are not going to spoil the relationship radically, just behave unpredictably: sometimes flatter, then offend. If your praise is very pleasant, and the offense is not deeply hurt, he will suffer, but the relationship will become brighter. Although this tactic is not suitable for all girls, but only for those who subtly feel the mood of a man.
Making a person suffer is not that difficult. But before you do this, ask yourself - why do you need this. If this is an attempt to prove your worth or demonstrate your superiority, it can lead to the exact opposite result. And if this is revenge for the suffering caused to them, then be prepared to break up the relationship. After all, people create them in order to be happy, and not for mutual torment.