If you listen to samples in isolation, you can be totally wrong about the sound. For example, when I first listened to the Appassionata violins just straight from the box, without them playing in a piece of music, I wondered - is that too much vibrato? But no - when they are in context it is perfect. In fact, it makes them have the best sound of strings that you can get in any sample library. Others sound dead, thin and whiny in comparison. Of course they have inconsistencies, sounds that are irregular, etc. But that is why they are so good.