One of Brian Eno's rules. You meant to do that out of tune note ;)
As for the guitar itself it is so relaxing and it has a sense of folk music to it. A sense of hope you know. The background sounds to it has that feeling to it like you are on a forest full of snow with below zero temperature. This is a nice way to structure this composition build the guitar as the dominant instrument and have the background be so athmospheric. 5/5.