What kinds of information would Michel Crevecoeur have included to a private letter to a friend that are inappropriate for an epistle?

In a private letter to a friend, Michel Crevecoeur might have included personal anecdotes, intimate feelings, or candid opinions about people and events that would be considered too informal or subjective for an epistle meant for a broader audience. He could have shared gossip, family matters, or his own frustrations with societal issues in a way that would not align with the more formal, reflective tone of an epistle. Additionally, private discussions about political views or critiques of specific individuals would be inappropriate for a public letter.