To quote Joe Satriani (slightly paraphrased) "There are no rules, only rulers". Rulers don't tell you how long or short to make something. They just put a label on distance. Some people could say "I don't use rulers to measure distance, I just use my eyes". Most people would say that is silly, since it wouldn't make sense to deny yourself the powerful tool that rulers offer.
Now take that analogy and apply it to music. Music theory is a collection of "conventions" that produce specific results. Use this knowledge to your advantage or ignore it, it's up to you.