As someone else pointed out, there is a natural instinct to avoid being the center of attention (unless you happen to be egocentric in the first place ). This is why most people prefer to avoid having to give speeches.
When I was growing up, I was terrified of standing in front of the class for any reason. Even though it’s been well over 30 years, I can still remember having to go up to the blackboard to write out a math equation in front of the rest of the class, or write out a spelling word, in first grade. I was dyslexic at a time when dyslexia was not recognized as a disability, so I regularly wrote letters backwards, or reversed digits in numbers. When I did this on class papers, the teacher simply marked it wrong. When I did it at the blackboard, the teacher pointed out the mistakes to the rest of the class, making me feel like less than nothing. For the rest of elementary school and into middle school, it was impossible for me to stand up in front of a group of people to talk for any reason. I was a good student, and made a lot of effort to make up for the dyslexia, but I was also introverted and rarely volunteered any information in class.
In junior high, though, I helped my mother with a play that she was in at the local community theater. In watching the rehearsals for the play, I realized that all of the actors were simply pretending to be someone else. I decided that if I could pretend to be someone else, I could certainly act in a play, so I auditioned for a play, and actually got a speaking part. That led to several active years in the local community theater, as well as the high school drama club (where I was often in plays, but also acted as director for several plays).
Now, I am a university instructor, and I’ve been teaching for nearly 20 years. It means that I regularly stand up in front of a group of people, and run the risk of making a fool of myself. I do make mistakes, but I’ve accepted the fact that everyone makes mistakes, and I don’t really care if anyone judges me only on the mistakes I’ve made in front of a class. However, I’ve also learned to “act” and improvise while teaching. The “me” that stands up in front of a class to explain how to use a particular feature of Word is definitely a different “me” from the person who hates having to figure out small talk at a party, and who jumps when the telephone rings.
In other words, I’m still basically an introvert, and prefer not to call attention to myself when it’s not necessary. However, I’ve learned to adapt by accepting the fact that no one is perfect, and I do have the right to make mistakes, especially if I am willing to accept the mistakes, laugh about them, and correct them as I recognize them.