Why does Gemini have dual personality?

In astrology, Gemini is a constellation guarded by Mercury, which brings wisdom and understanding to Gemini. So the difference between Gemini and many constellations is that many aspects of thinking are purely rational. Most Geminis will think about whether I want to be with this person or not, instead of: Do I love this person? The second characteristic of Mercury is that Gemini will become quite interested in many things. Gemini has an enviable talent, that is, the ability to read widely. Many Gemini can read many newspapers or BBS. There are so many reasons why there are fifty or sixty people who are my favorites, because they have nothing in particular. When such essence and characteristics correspond to feelings, Gemini is more likely to find others' goodness than ordinary people, because Gemini's heart is not purely emotional, but when Mercury is widely read, Gemini's emotional contact surface will be abnormal. Simply put, Gemini is self-centered and then reacts radially to many objects. There is another reason why Gemini has scattered emotional luck, because Gemini's way of thinking is biased towards rational thinking. This rational thinking is too indifferent, and this indifference will make Gemini partners often angry and unable to follow. For example, when Gemini goes out to eat, she will feel that it's nothing for others to find me, so I will accept whatever others give me, so Gemini often makes herself seem to like you, but in fact Gemini doesn't think so at all, so Gemini becomes the most double-faced person in 12 constellation.