A credible person does not require embellishment to make facts impressive.

Decoration is usually a sign that the underlying material is thin, or that the speaker does not trust it to land. Real accomplishments hold up in plain description; they do not need the extra adjective or the rounded-up number. Once someone notices the decoration, they start wondering what needed covering. The embellishment ends up undermining what was already good.

Tell a recent success this week with no adjectives and no inflation, just what happened and what it took. Notice that it lands harder rather than softer. Plain delivery is what makes people believe the content.