Traditionally, the character of "satan" in literature is friendly, charismatic, clever, and amiable. Often, he is depicted as being unable/unwilling to tell a lie. He does, however, refrain from revealing the whole truth.
He promises us whatever it is that we want most in life, and he delivers it, as promised. And at first we are very pleased with the arrangement. But in time we begin to discover that the thing we wanted so badly is turning out not be as wonderful as we originally thought it would be. And of course the 'deceiver' did not tell us this would happen. He didn't tell is it wouldn't happen, though, either. In fact, he didn't lie, he simply let us deceive ourselves with our own desire.
Eventually the "gift" we wanted so badly becomes a horrible curse, and our lives become a living hell because of it. And there is no way to 'undo' it. The lesson of these stories should be obvious to us, but we humans are a selfish, greedy, short-sighted lot, and we fall prey to our own desirous deceptions all the time. Which is why these stories in one variation or another have been around so long.