I asked some friends who are not even very computer-savvy to try "Lost Pig" and they became engrossed after a few minutes of user-interface confusion. I had always thought the confusion would be enough to put off the average user (and still do not believe in IF as a profitable venture), but each of them greatly enjoyed the game and wanted to continue playing longer than my laptop was available to them.
The Hitchhiker's Guide to the Galaxy was my first experience with IF, and it was very frustrating, but in a way that entertained me greatly. The game unforgivingly kills the player again and again for oversights so ridiculous that the player was obviously not expected to even guess at them until after dying. If that's not something you enjoy, the deliciously witty prose is worth the effort, even if you resort to using a walkthrough, step by step.