gente boa is used as an expression meaning "what's brow?" (e aí, gente boa?) bit it would sound awkward in this type of sentence because "nós somos" take the sentence to plural.
Por isso devo escrever :
A gente é louca
ou
As pessoas são loucas
obrigado ...
I need to check my english ... i kept doing mistakes such as my bride-dress (forgetting the possesive and so on ... I also need to check difference between People and The people ..
Randomly we must use People without The, but sometimes with must use The people, most of the time pessoas is forbidden ... but not on this last question.
Because we use "povo" referring to a people in a certain region (residents and people who is in a nation/country, most of the time). But it can also be used informally to refer to a lot of people.