It's one of those central tensions that can either make or break a story for me. When a character's been alive for centuries, watching everyone they ever cared for turn to dust, you'd expect a certain level of detachment, right? But the good ones don't just have them become emotionless monsters. Instead, they often make the emotions more intense, almost overwhelming, because they've got this vast archive of memory and loss to draw from. They might have learned to control the outward expression, but the internal storm is still there, magnified by time.
I've always preferred when the 'struggle' is less about lacking emotion and more about managing its sheer volume. Anne Rice's Lestat is a great example—he's perpetually bored and cynical on the surface, but his actions are driven by this deep, romantic, and often possessive love and hunger for experience. It's not that he doesn't feel; it's that he feels too much, and it's all filtered through this immortal perspective that can make him seem capricious or cruel. The human emotion is there, it's just... distilled, aged, and sometimes dangerously potent.