Every craft has a level of detail that will often go unnoticed except by other craftsmen. I can appreciate a painting but an artist will appreciate the brush strokes. I can appreciate the way a movie looks but a phototographer will appreciate the film grain. I can appreciate your great lyric but Pat Pattison will notice your additive rhyme creating stability in your chorus.
Here are two lines. The first end with please. A long 'e' vowel sound ending with a 'z' sound lengthening the word. While the second line ends short with flee leaving only the long 'e' vowel sound.
There was a time I was ready to please
Now is the time when I'm ready to flee
This is a subtractive rhyme. The long 'e' vowel sound gives the words there similarity but because the second line ends with less sound it leaves it a tiny bit unresolved. There is a tiny part of your brain that is trying to fill in the length of the two lines and wanting more to come of the song to fill that tiny space left by the missing 'z'.
Here are the two lines again with the two last words reversed.
There was a time I was ready to flee
Now is the time when I'm ready to please
Not only does reversing the words change the sentiment but the tiny change of adding the 'z' sound creates a resolution to the lines that was lacking in the first version. This is an additive rhyme.
I compare this incredibly subtle tweak to a designer shifting a line by a single pixel. You may not notice that it happened but you'll appreciate the effect when the shift is in the right direction.