Well, by reasonable context. I'm sure we can all come up with fringe cases where the thing's just a UI disaster. For any reasonably designed bit of software tho

Well, by reasonable context. I'm sure we can all come up with fringe cases where the thing's just a UI disaster. For any reasonably designed bit of software though, it's hard to imagine it being hard to use - especially when you've already used something in the same general class.