TL;DR most people think of introvert/extrovert on one dimension, but in fact some people are both (happy alone, happy in groups) and others are neither (unhappy alone, unhappy in groups). So it makes more sense to think of it as two dimensions (some nice charts in article to visualise this).
Since reading this article I've tried to become more "extrovertable".
Not for everyone - for many it might be best to focus on a single dimension, but it's helped me thinking about it in 2 dimensions and explicitly practicing becoming better at both "skills".
[0] https://www.inc.com/joshua-spodek/there-are-no-such-things-a...