Final answer:
The evidence provided does not show Peter's nasty nature, but rather his human reactions such as skepticism or disbelief in certain situations, which are depicted in religious texts and artistic representations like those by Caravaggio.
Step-by-step explanation:
The question appears to be focusing on the character of Peter as depicted in various contexts, including religious texts and artistic representations. However, the evidence you've mentioned doesn't reveal a 'nasty nature' of Peter, but rather shows him being skeptical or disbelieving of the miracle Christ performs with the fish or preaching for a cause like the First Crusade. His disbelief in the miracle is noted, and in historical context, he is a complex figure associated with both piety and human failings. The confusion and disbelief are natural human reactions that can be seen as a part of his character development rather than evidence of a nasty nature.
Furthermore, Caravaggio's secular depiction of religious figures in art like 'Crucifixion of Saint Peter' highlights realism, not necessarily the nasty nature of the subjects he depicts. It is important to distinguish between Peter's human reactions represented in various scenes and the overarching assessment of his character.