the imo thing has to do with rhetoric and not the individual's appeal
totally repeating what trinick said p much but
typically, if you directly highlight that a statement is a claim of personal value (e.g. "In my honest opinion, toasters should have never been invented."), the statement itself has a lesser "impact" than if you were to make the statement alone (e.g. "Toaster should have never been invented."). of course, the credibility of a claim is only as good as the details supporting it.