When we interact with items we usually right-click them and select an action to be performed. For frequently performed common actions this is not very user-friendly, so why not define a "default action" for an item and let us just double-click the item to invoke this action (instead of just examining it)? For example, the default action for a ladder (when you are standing at the lower end) would be "Climb Up", while you would probably want to "Open" a closed chest when you double-click it: ...