You care about what others think of you.
You are afraid that you will become careless when you become cheerful.
You are afraid that if you become strong, you will become selfish and then others will stay away from you.
In fact, introversion is not a problem, there is no need to be too entangled. I can also say that your present consequences are not caused by introversion, but by your inferiority and vanity. I feel that I can't do anything well all day, but I'm afraid that I can't do it well and others will say you. Although I don't know if others have said it, I feel that others are talking about you. In fact, you think too much of yourself. No matter what you do, as long as you do it with your heart, you don't have to care what others say. In fact, there are some things that others don't have time to worry about, because they also have many things waiting for them. Therefore, it is your own inferiority complex that makes you feel that many people care about your practice.
On the other hand, cheerful people are not all careless, and cheerful personality is just an attitude towards people. Because a person's heart is big, he is willing to look on the bright side without increasing his troubles, which is what we often call optimism. In fact, what you should worry about is whether you can become such a person, not what the consequences will be.
Finally, strong quality will not make you selfish, because people with excellent quality are not selfish. Good quality can only show that a person's psychological construction is excellent. In the face of all kinds of situations, we can treat them with a rational eye. In fact, this is not a person who wants to get better. This can only be done by combining one's own personal experience and unique opinions.
Therefore, what you need to do now is not to care about what kind of person you will become after the change, but how you should become that kind of person. Because a person's personality, after entering adulthood, is difficult to change, and it is not achieved overnight. Need all kinds of knowledge and insight to adjust slowly.