Of the motive of Iago‘s malignity

After reading a few classes, what I find most interesting is not the image of Iago who is almost fixed as a villain, but why he changed from a man who would not have revealed his dissatisfaction to the image of a villain today. He was full of self-confidence and was sure to get the position he expected. But when he learned that he didn't get the position he thought he should have, he was depressed, he was angry, he was dissatisfied. In my opinion, his sudden evil is not sudden, it is a matter of change. This change is the result of both internal and external factors.

Let's start with the internal factors. Iago had ability, ambition, and perhaps ambition. But he is not a sage. Naturally, he is full of resentment for what he has imagined but failed to obtain. Let's talk about external factors. When the society observes everyone with colored glasses, no matter what kind of people they are in, they are so insignificant. The sufferings in his life were a heavy blow to him from the outside. Finally, under both internal and external factors, Iago, who was normal and could suppress himself, was covered up by his own evil thoughts.

In the end, we can see that he is indeed a very selfish person who only cares about the gain and loss of his own interests. The root of his vicious conspiracy lies in Othello's refusal to be his own deputy and only let him be a small flag officer. This incident made him feel that he had suffered a great loss. It also made him start to do all kinds of evil and show his image of being a sycophant.