It's not a direct answer, but I'll share a character I came up with once that maybe shouldn't have worked, but it did.

I played a character who was quite genuinely the crown prince of a large and wealthy kingdom... but was such an idiot that the kingdom convinced him to go off on an adventure ("we need you to go save the world!") so that they could be governed by someone competent instead while he was gone. A good person, but just very suggestible and airheaded, with some Don Quixote type stuff mixed in for good measure.