The Principle of Least Change in Music

(At your risk).

Least change has great impact on mind perception.

For example:

You Do Something to Me - Paul Weller

The song is written in E minor.

So the first bass is E.

Paul sings E #F G B while bass is E.

Then repeats B while bass goes down to D creating an interval of major 6th.

Then bass goes down to A but as there is nothing at that moment sung the mind of the listener has the perception of prepared major 9th since the distance between bass A and melody B is 9 steps of the scale.

For more please read the book: "A Letter to Clive Davis" - euroelectron

Further reading:

The Bach Manual for his students in composition which can be found at the appendix of Bach's biography by Spitta. I do not know if it is included in newer editions, please check.