I take your question to mean: "Have you ever just formulated a recipe on the fly with no consideration to what style it is"
I would say absolutely yes. I have done a number of experiments in brewing that have turned out great.
It is great to re-create an 800 year old style, but I liken brewing to cooking (which I also enjoy thoroughly), not necessarily "a little of this a dash of that" but "3 lbs of this, 6 of that, let's try this hops that I have never used, etc."
My most recent success was a 3 batch experiment where I used only pale malt, one kind of hops, and one odd adjunct.
I made one super cheap but delicious IPA, a roasted pumpkin seed ale that is good, but it showed me that I am damn well going to make a pumpkin seed porter for next year. And I made a habanero ale that is off the charts. My mom even loves it. I know you don't know her, but picture a typical "mild" mom.
I learned more about bullion hops, cascade hops, pumpkin seeds, light malt, and peppers in breweing than I ever would have by brewing other people's recipes.