Altering the mood of your song or patterns.
Mood is changed by what "mode" your music is written in. Seven distinct moods/feelings, from godly/ethereal/ambient (Lydian), down to pure evil (Locrian).
This is the table of modes in order of feeling/mood:
; Modes Intervals
; 1 2 3 4 5 6 7
Lydian: defb 0,2,4,6,7,9,11
Ionian: defb 0,2,4,5,7,9,11
Mixolydian: defb 0,2,4,5,7,9,10
Dorian: defb 0,2,3,5,7,9,10
Aeolian: defb 0,2,3,5,7,8,10
Phrygian: defb 0,1,3,5,7,8,10
Locrian: defb 0,1,3,5,6,8,10
You can use this table to adjust the "spelling" of the scales to change moods. Ionian is the standard Major scale, Aeolian is the standard Minor scale. Lydian, Ionian and Mixolydian are Major scales. Dorian, Aeolian and Phrygian are Minor scales. Locrian is known as the half-diminished scale. It has what's called the "satanic" interval banned by the Christian monks, the flatted 5th.
Mixolydian is what most "happy" blues uses. Dorian is for "jazzy". Phrygian is "Spanish/flamenco", lots of heavy metal uses it also. There are lots of other non standard modes like Phrygian Dominant, which has a Major 3rd, the 3rd interval raised one semi-tone, the standard Flamenco/Spanish scale, 0,1,4,5,6,8,10.
The table can be extended to 13 intervals for the spellings of all known chords. Standard chords are just the 1st, 3rd and 5th intervals. But there are also 7th, 9th, 11th, 13th chords in both Major and Minor flavors. This would be useful for having ornament presets.