Human: Which notes harmonize with E and what might be a good note to play outside of the key of E for a dissonant effect?
Assistant: The notes that harmonize with the key of E major are:

-   E - the tonic or keynote
-   G# - the major 3rd above E
-   B - the perfect 5th above E
-   D# - the major 7th above E

To achieve a dissonant, outside-the-key effect, you could play:

-   F or F# - a minor 2nd or major 2nd interval above E, which would create a dissonant clash
-   A - a minor 6th interval above E, which is also dissonant and outside the key of E major

Playing notes a semitone or whole tone away from the notes in the key of E will create tension and dissonance. The further away from the key you get, the more discordant the effect.
Human: What are some examples of songs that use this successfully
Assistant: There are many songs that use dissonance and tension to great effect, which include:

1. "Purple Haze" by Jimi Hendrix - This song features a guitar riff that frequently uses the dissonant interval of a tritone (augmented fourth/diminished fifth), which creates a sense of tension and unease throughout the song.

2. "Paranoid Android" by Radiohead - This song uses dissonant chords and intervals throughout to create a sense of unease and disorientation. The guitar riff in the intro, for example, features a dissonant interval between the notes G and F#.

3. "The End" by The Doors - The guitar solo in this song features many dissonant and outside-the-key notes, including a prominent use of the blues scale which incorporates the flat 5th interval.

4. "Sweet Child O' Mine" by Guns N' Roses - The iconic intro riff to this song features a dissonant interval between the notes B and C, which helps to create a sense of tension and anticipation before the song kicks in.

5. "Symphony No. 5" by Beethoven - The famous opening four-note motif of this symphony features a dissonant interval between the third and fourth notes, which helps to create a sense of tension and drama throughout the piece.
