Right, in text adventure games it is very easy to code a one-way door (e.g. "your brother Ralph has been kidnapped!") and a door which requires a key (e.g. "if you have the voodoo doll you can give it to Alice, who will then open the portal to the underworld"). If the one-way doors are dynamic (e.g. "if you tell the police the secret, then you piss off the mob boss: afterwards any attempt to go into the mob lair leads to death and restarting from the last save point") and you are not paying careful attention, then that key might easily be in an unreachable part of the game ("crap, if I wait too long to get Ralph back and, before that, I piss off the mob boss, then I can never get the voodoo doll from Ralph, and so Alice will never open the door to the underworld and now there's nothing left that I can really do").

It is especially important because of how frustrating the resulting loss is; it does not even have the dignity that you get from killing Vivec in Morrowind, where the game informs you "sorry, this game just became unwinnable." You just wander around after doing a bunch of actions that made sense at the time, not realizing that your brother Ralph was twisted up in some crazy voodoo plot. "Yes, Alice, I see that you have pains in your arm that you think come from some voodoo doll, I don't see how that has any relevance to anything though: I've searched this whole damn city and there are no voodoo dolls anywhere." Until later "Oh wait... there was that one alley on the other side of the mob lair, it looked empty at the time but what if that's where Ralph is now?"