every so often I would get stuck even though I knew exactly what it wanted me to do

That was a problem every once in a while on an Infocom game. I usually considered those to be design flaws. The point of the game is not to argue with the command parser.

One I remember in particular had to do with playing a life-size game of chess. Most of the pieces were easy to move, but you had to figure out just the right syntax for the knights. It wasn't "n.n.e", but "n then n then e". Very annoying.