I think the most interesting character conflicts are when the people are similar but just have different assumptions or priorities. I have a novel where the villains are aliens who just want their home back --- too bad they want to genocide the entire human race to get it (!)
All introvert means is "gets energy from being alone," while all extrovert means is "gets energy from the outside world." MRI scans show introverts brains have a cascade of reaction from the smallest sensory input, while extroverts brains, when deprived of input, tend to more-or-less shut down.
My best friend is a social introvert, and needs her down time, but she can easily go to a noisy group gathering of her family and be totally fine, while I'd be running for the door. And she is far more likely than I to reach out to talk to a friend, family member, whatever.
I'm an extrovert and very chatty to my close friends, but get overwhelmed quickly in group gatherings (that could be the Aspergers --- a fun combination that --- extroverted Aspergers

). In real life, I reach out to specific people I'm close to, but anyone else I'll be polite and friendly but won't initiate anything, really.
Psychology is a fascinating subject, because it's so complex.