At certain points of the menu system enter will default to a certain option. Usually it's back to the previous menu, but some times it's to acknowledge a yes/no question. This is preference for me, but when you use a ration and it asks you if you're sure, can that default to yes instead of no?
I had to actually die [of starvation] and become resurrected again before I figured out that I wasn't actually eating a ration...even now I still hit enter thinking I've eaten a ration...

The only other instance I've find where the default <enter> could be changed is when you're going up/down holes (it defaults to No). If you go to use the rope while you're on top of a hole there's a pretty good chance you meant to. In anycase it's primarily the ration one that gets me.