Even in the middle of eating and singing, celebrating after the unbelievable victory of the Straw Hats against CP9 and the Buster Call, Usopp couldn't shake the worry off his mind.
He had left the crew. He had left his nakama for his dear ship that now lay charred in the bottom of the ocean, and still Luffy didn't know he had fought together with them. It was pretty safe to assume that, as the captain was horrible at lying, and there didn't seem to be any doubt in his eyes when he listened to Sogeking's stories of his heroic adventures.
Usopp was good at not remembering unpleasant things when he didn't want to, almost professional, but he could not shake off the hollow, gripping feeling that returned to his stomach every time he got a moment alone in the middle of the crowd. There was something he should do, something he sure as hell wasn't capable of. He should go talk to Luffy, as Usopp, the one who abandoned his nakama, and ask to be let back into the crew.
He couldn't do it, but couldn't really not do it either. What would happen to him if he was left in Water Seven, all alone in an unfamiliar place for the first time in his life? He had set sail to become a pirate, and that he had done, but what would he be if he was left behind with no boat, no crew and no courage? He wandered aimlessly among the celebrating crowds and ended up standing in a wall's shadow behind the grills. Usopp had never been seasick; on the contrary, the concrete and solid rock below his feet was making him feel ill. Its flat pressure weighed the soles of his feet and he felt like jumping to avoid the feeling. He was bound to the ground and didn't know how to get away.
"Hey there, Sogeking", Sanji said, making Usopp jump. He had been deep in thought and Sanji, who apparently hadn't been quiet at all walking up to him, raised his eyebrows. Or one, you couldn't really tell.
"Why hello, Sanji-kun! I was just meditating away from the crowds. A true warrior must always keep his mind strong!" he said, words that sounded suitable flowing with ease.
"After you ate half as much as meat as Luffy, yes. I'd call that an archievement, by the way."
Thinking of Luffy, something inside the long-nose broke down. He fought against tears behind his mask. Maybe he should keep it, it was pretty convenient.
"So, Sogeking, do you suppose Usopp is planning on returning to our crew?" the cook standing beside him said, without noticing the change in his companion.
"There is no Sogeking!", Usopp half shouted, unable to keep his voice from jumping. "There is no legendary sharpshooter or killer of the giant goldfish or Island of Snipers! It's all a lie, and a bad one at that. I never lived up to the role, and I failed and I ran away over and over again. I can't ever face Luffy again!"
"Usopp.." Sanji blurted, surprised by the outburst. There was a short silence where the sniper got more and more embarrassed of what he'd said every second, and Sanji had an unreadable, contemplating look on his face.
"You know, I told you already that everyone has things they can and can't do. Sure, you were cowardly, but what you did, you did pretty well." He breathed deep, as if to calm himself down. "And you said it yourself, didn't you? The Island of Snipers is in your heart."
Usopp blinked and looked up at the cook. Sanji wore an expression of badly-hidden uncomfort and embarrassment.
"This was the only time I'm saying anything poetic like that to a man ever, okay? It's wasted and feels disgusting. But, I'm telling you, everyone wants you to come back. You just need the guts to ask." He kicked the grass in the flowerbed as he strode away.
Usopp felt a small gush of warmth in the hollow place in his stomach and on his cheeks. Yes, maybe they would take him back— No, they would definitely welcome him back. Obviously they were in trouble without the great Captain Usopp!
He was kind of hungry again. The meat on the grill where Luffy and Chopper were stuffing their cheeks sure smelled good!
As they say*, the rest is in canon. Usopp got too confident and tried the wrong approach and Sanji was like WTF, bro.
(I just really wanted to write a fanfic where Sanji comforts Usopp by quoting that line of his. And while rereading Water Seven, I found a pretty good place for it.)