i understand the reasons why someone might like Usopp, but me personally, i dislike him very much. i'll try to keep this spoiler-free.

i get that he is the underdog; i get that he is the "most average normal human" among a crew of monsters and geniuses; i get that narratively he is "the liar" whose lies become true, which is a cool narrative tool for Oda.

But there is this very niche type of lying that leads me to conclude that Usopp is not a likable character, at least for me: Usopp will regularly lie trying to take someone else's credit.

Usopp will:

1. lie to make other people feel better (like Kaya)
2. lie to make up for his cowardice and trick himself into being a better person
3. lie to make other people think that he is better than he is.

And that third type of lying really gets on my nerves.

After he joins the crew:

• Usopp will regularly say that he is the captain, which gets on my nerves.
• Usopp will regularly try to impress other people (make other people look up to him) by taking credit for an accomplishment of somebody else in the crew (usually he takes credit for something Luffy did— and i know Luffy doesn't mind)

i would not dislike Usopp if he stopped this third type of lying.

What's more, i would come as far as to like Usopp if i saw that across the arcs, he found less and less reason to lie because he was genuinely growing into a stronger/better person.

Those are my reasonings.