I don't personally play any text adventures any more, but I loved them when I was a kid. But the problem you talk about (getting stumped, fighting with the interface) is an unfortunate aspect of all too many examples. Getting the difficulty right is one of the most difficult aspects of making an adventure game, text or graphic. That's why I think that it takes a true master to make a great adventure game, because you have to not only have brilliant ideas yourself, but also be able to put yourself in the heads of un-brilliant people and anticipate their decisions, smart and dumb. That means having command of psychology, technology, and on top of all that, creativity and writing.

From what I've seen, the biggest mistake is to assume that a player will approach a problem or puzzle the same way you would, when in reality we often take very different approaches. Something that makes perfect sense to a developer could be totally lost on a player. Also, sometimes players just won't see something right in front of their face. Just a little nudge or poke is all they need, but if it's not there they end up having to look at a walkthrough and that ruins everything.

Ultimately, I think games have conditioned us to think there is one right answer and one right way to win. That's unfortunate, because we *should* be able to take away something meaningful from a game that we "lose." Not every good movie has a happy ending. It seems odd that any "bad endings" in games are merely a failure from the player's POV.