One of the main characters in DS9 was a member of an alien species called the trill. And the trill are two-part life forms. They’re two separate organisms. A humanoid host and a slug-like organism called a symbiont that’s surgically shoved into the host’s abdomen and grows into its central nervous system. Each is its own thing. The host and the symbiont have different personalities, minds, memories, the whole thing. And the trill’s personality and mannerisms become a unique blend of the two different entities. Eventually, the host dies. It’s got a normal humanoid lifespan. But the symbiont can survive and get implanted in some other host with all its previous memories intact. And the new trill’s personality and mannerisms become a synthesis of the new host’s personality and the symbiont’s personality based on all its lifetimes of experiences and memories. And that’s how role-playing works. Role-playing isn’t pretending to be someone else because you just can’t ever do that. Like it or not — and lots of people resist this basic truth — you can’t take the you out of role-playing. Whatever character you play, you’re still the slug in the character’s stomach. All of your own personal experiences, beliefs, perceptions, attitudes, ideas, and priorities come along for the ride. In the end, it is still your brain making whatever decision the character makes. And your brain’s decisions are the result of its wiring. And your brain’s wiring is a result of your genetics and biology and how your brain’s wiring has developed in response to your experiences. Nature and nurture. That old yarn. You literally cannot think like anyone other than you for the same reason you can’t bend your knees backward. It’s a hardware problem. Besides, to think like another person would require you to hold an infinite set of memories, experiences, beliefs, priorities, natures, and so on in your head. Perfectly. Because all of that s$&% figures into every decision you make, no matter how simple. And, guess what? You can’t do that. Role-playing’s thus not really about pretending to be someone else. It’s about making the choices you would make in a given situation if you were a certain character. Role-playing is saying, “okay, so, this dragon is descending on the town. What would I do in this situation if I was a bada$& barbarian dude from the hill tribes in some fantasy world?” The question’s not “what would Angrar do?” It’s “what would I do if I were Angrar?” It’s a subtle distinction, but super important. The character you play is always “you, but…”
a great explanation of how to role play a character