It depends on who you're trying to impress. Evidently, the members of this forum are NOT impressed by Fantasie-Impromptu (there was another thread about that piece being a show-off), but whenever I play it for my friends and family, they are completely awestruck.
The other day, a beginning student of mine asked what the metronome was. I set it to a slow tempo and played his *ridiculously easy* piece (I think it was Lightly Row) along with the beat. Then, I showed him how the metronome can be set at a really fast tempo, too. I played his piece again at 200 bpm and his mom just about fell out of her chair. She was like, "Holy cow, you're really good!" Haha, see, some people are easier to impress than others. So tell us who you are showing off to.