@Hyper:
So uhhhhhh, when is the "Brave Captain Ussop" lie going to come true?
Well, that's argumentative. I read a war novel "All quiet in the Western Front," wherein soldiers thought it was perfectly reasonable to soil yourself after your first time in battle. Of course, it's fiction, but it's written by a war vet. That book really gives you a unique perspective on fear.
Anyway, what I'm saying is that in some ways he's done it already. Like by standing up to Mr.4, Enel, and Jyabura. But things like running away from the Cerebus shouldn't be a big deal, I mean, what does he have to prove there? The absence of fear doesn't make you brave, if anything it makes you an incomplete person.
Should we hope that Sanji and Nami get over there fears of bugs in the meantime? And hey, where's Zoro going to get a sense of direction? Probably never.
But my point is that, I don't get why things like running from harmless threats like the cerebus or erring on the side of caution are huge and annoying character flaws. It's not like Usopp won't stand up and fight when the time comes for it, i.e. when it actually matters.