In life, sometimes you're able to do something easily that appears very difficult or impressive. Consider a card trick. It might simultaneously be easy for you to learn to perform while impressing your audience.
On the other hand, you might do with great difficulty something that others perceive to be easy. For instance, drawing a perfect circle free-hand on a piece of paper might look easy but in fact it takes much practice to achieve consistently.
Are there adjectives to describe these two cases? That is, feats that are difficult but appear easy, and activities that are easy to perform but appear daunting.