All one ever needs are the good manners. The rest is just silliness and snobbery valued only by bores.
I believe there is a difference between etiquette and manners.
The first is a set of rules though established with the purpose to minimize and prevent socially awkward situations but can also serve as an elitist way to exclude certain people or groups and ostracize them for their ignorance regarding the proper use of a fish knife.
Manners on the other hand are an outward expression of internal personal values. They can never be rehearsed. At the core of good manners is the desire to be kind and inclusive and respectful.
Good manners are universal, etiquette is strictly limited to a certain social circle.