Before Nami was ever a navigator, she had been a thief and con artist. She had unashamedly led people around, and not in a good way. There was no dispute that it was one of her greatest skills, outside of cartography.
Sometimes she would stay up late at night and wonder what horrible damage she could do. With few exceptions, the Straw Hat Pirates didn't have a whit of sense. Even Robin was more apt to go with the flow than to speak against one of Luffy's insane plans. It was more amusing that way, she would say quietly while Nami banged her head against the wall. Amusing and entertaining.
Nami preferred to substitute the words stupid and illogical, but in the end it was a matter of semantics. Luffy got what he wanted, and what Luffy wanted was adventure.
But…a small portion of her mind would whisper on such nights…You could get him to stop if you really tried. It doesn't take much to distract a moron, after all.
Shut up, Nami would answer, too frightened by her own influence to be worried about the fact she was talking to herself. Sometimes it was scary knowing how easy it was to manipulate her friends, how a coy smile and a well-placed word could get them to do whatever she wanted. Nami navigated. She led, sometimes in more obvious ways than Luffy ever did.
The Nami who spent eight years scrapping for money and power was pleased at the thought. The Nami who spent a lifetime trying to understand what it meant to have a family, less so. There was a struggle within her, a duality that struggled for dominance. A part of her that saw people as tools to be used, which fought against the part that saw people as deserving of respect.
But it was so easy. Chopper and his youth was naïve, Sanji and his eyes for anything with a pretty face love struck, Luffy and his idiocy easily sidetracked, Zoro and his honor effortlessly manipulated, Brook and his trusting nature simple to mislead, Usopp and his fears trickable, Franky and his temper putty in her hands.
Robin's paranoid personality would probably be the most difficult of all, but even she wasn't above Nami's ability. After all, Nami had been Robin's first real friend among the Straw Hat Pirates. It was inevitable considering the living arrangements that Robin knew Nami best and vise versa. And when one hadn't had even a single friend in twenty years or longer it was easy to see how a normally level headed, rational person might somehow become decidedly less rational where those friends were concerned.
Sometimes thinking of how she treated Luffy when they first met made Nami sick. She had thought she had everything in her life under control, when really she had been standing on a house of cards that collapsed on itself.
The solution to these fears—the nightmare that she would someday send her crew into a storm that would tear them apart—was to not lead, but to guide. By outward appearances Nami had more control over the crew than Luffy did, but she was not the Straw Hat's captain. If someone looked close they would see how Luffy had a better grasp on his crew than any other. His was an odd sort of captainship, but there was no doubting his authority.
After being freed from her past, Nami had become a navigator. Her job wasn't to stand ahead of her crew and yank them where she wanted to go, but to stand beside them and point out all of the possibilities.