I don't get why people look at music theory as a set of rules. Its not "rules", its a language. A way of communicating ideas efficiently. It doesn't set down any "you can do this, but not this" type of thing. Its merely giving names and explanations for the relationship between different notes.
Let's see if we can get passed the language differences. I am an older guy, so my language is maybe different.
Rules, is an annoying off putting term, but that is the term I was taught, and call it guidelines, or restrictions or have at it.. when my teacher said no parallel fifths, that to me was a rule not to be "violated".
It's not that i didn't wonder, "Gee I wonder if Mozart ever did parallel fifths in his music?"... yes, I wondered, and still wonder- I also know he DID use FIfths on occasion.
But here is what is so vital.. a few things
The restrictions, or rules, inadvertently guided me to sound closer to a certain style of music that was previously beyond my grasp. Why, because the music that I was studying was from a prior century, and back then they had all sorts of rules. If you don't adhere to the rules, like a recipe, you will not get the desired musical genre. It is impossible to sound like Mozart if you don't adhere to his 200 year old musical map, so called "restrictions" and all.
Even better than that... I was so pleasantly surprised to find out that all of the many rules in early counterpoint ( note against note ) gave me the MUSICAL GIFT i can barely explain. It taught me about the tones in a way that would be impossible to be sensitive to, without first learning to create with much much less freedom of choices... such as no parallel oct, or no unprepared dissonances.
BAck in the day, you could not just play a seventh chord.. Oh no, you had to FIRST PREPARE the ear with that tone ( in this case eg key of C major an F in a G7 chord ) which was ruled to be a dissonance, a G chord with an F in it ( a seventh )was ruled as a harsh dissonance, so the F was the dissonant tone, the PREVIOUS chord had to contain that F but in a CONSONANT environment, namely either a Dminor or an F major, in both cases, the F is heard as very CONSONANT, THEN the F would be held over into the succeeding G chord..where it was, so to speak, SUSPENDED as a DISSONANCE. this is called preparation of the dissonance and finally resolution in the following chord. meaning the dissonant tone ( F ) HAD TO resolve ( ONLY in one direction ) , DOWN a DIATONIC step. So Preparation chord, dissonant chord and resolution.. 3 chords to deal with one meager seventh!!! Amazing.. but in that restricted world your ear gets very very sensitive.. like eating only apples.,, the day you eat a peanut, oh boy, does that peanut taste good. Your ear becomes very discerning to what before was just another ( another peanut!) 7th chord, big deal. No, it was a big deal, I learned the big difference between triad and seventh and between consonance and a little more dissonant in the baroque system. The restriction is your friend. Back in the day we heard the polarity "freedom within the Form". Learn the Form only then can you gradually be free of it. I think dropping early counterpoint is a very bad idea, for these reasons; regardless of what modern music you wish to study.