There are two types of people. Introverts and extroverts. And believe me, it is not easy being an extrovert neither introvert. The best is, when you are something between. You know, some mix. However, you will always be either more extroverted of introverted.
Honestly, it does not only have to be us, people being introverts or extroverts. Actually, you can spot this feature even on animals. I mean, just check this video of dogs jumping and screaming for the attention. Is it not just like when we are trying to be noticed?