Extroverts don’t pay attention to others. They are more concerned with flapping their own jaws, and interrupting others speaking, than with taking information in. The “extro-” refers to them spewing themselves all over everyone else.
Introverts pay attention to others, listen, and think before they decide to speak. They find joy in taking information in, and are less concerned with having their ideas heard at any cost. The “intro-” refers to them collecting information from outside themselves.