"Do not overwrite. Do not overstate." (Strunk and White, The Elements of Style)
I don't know why, but some people are just given to excess. I have a good friend who used to have many opportunities to introduce me before I spoke to a group I was training. He'd say things like "Steve is the paramount authority in the nation on such and such," going on and on about my eminent qualifications. Of course, I wasn't anything of the sort. And yet he couldn't be stopped. He either believed it to be true or so much wanted it to be true that it became true for him. That's one kind of excess: exaggeration.
Make modest claims, and then you can be surprised. Don't think more highly of yourself than you ought, said Paul, "but in humility consider others better than yourself" (Phil. 2:3). Hyperbolic people are tiresome, because everything is "huge," "awesome," and "phenomenal." Such behavior undercuts credibility. Verbosity breeds contempt. As Stunk says, "Rich, ornate prose is hard to digest, generally unwholesome, and sometimes nauseating." As with prose, so with people.
A proverb says "a word aptly spoken is like apples of gold in settings of silver," (Pr. 25:11), and yet we can be prone to overspeak, as fascinated as we can be with ourselves. Strunk says "a single carefree superlative has the power to destroy, for the reader, the object of the writer's enthusiasm," and, we would say, the speaker's credibility and welcome as well.
Be modest. Avoid an overwrought speech or walk. Then you (or better yet, God through you) might surprise someone.