A case for making interfaces noun-oriented rather than verb-oriented:
What happens when we auto-complete f(x)? First we need to know all possible f that are valid in this context. Since the programmer has just started typing in the expression, any function is valid, and that means there's a very long list to choose from. It takes many keystrokes to pick one. Second we need to know all possible x that are valid in this context. These are usually local names, so there aren't that many. Knowing the type of f narrows down the list but the list was already small, so there's not much to gain.
What happens when we auto-complete x.f()? First we need to know all possible x. The programmer has just started typing, so any local name is valid, but there aren't many. Typing just one character can narrow down the list to one or two elements. Second we need to know all possible f that are valid in this context. These are methods defined on the type of x, so there aren't that many compared to all possible functions. Knowing the type of x narrows down the list substantially, so there's a lot gained.
And apparently, Amit started thinking about that as a result of running into Richard Garriot while shopping with his mom!