You must've been a clever kid and/or I'm a bit dense :) When I played most of the Monkey Island games as a teenager / young adult there were definitely several times when I had to resort to GameFAQs.
I don’t recall it to be as frustrating as say King’s Quest but then again it might be nostalgia.
I can attribute my debugging skills to playing these games as a child. As you had to be meticulous.
The only reason we beat these as kids was having a near infinite amount of time to waste.
And it was so, so easy to kill a cat. You use the automatic repeat-move key and auto-hit when you collide with a monster, and if you ever find a cat anywhere that way, its dead. People would rage-quit and start all over, it was that frustrating.