Someone on Sewing World asked what everyones 'Aha!' moment was in sewing...a realization that caused a paradigm shift. Some mentioned discovering the fit of European patterns, others when they realized they could cut between or outside of the lines on a pattern...my real 'Aha' moment came when I realized didn't have to rely on a pattern to tell me how to do something.
Back in 1982, I bought a pair of Liz Claiborn raw silk pants on sale and wore them for probably 10 years...until they really looked bad. They had the zipper in the pocket, which I just thought was the coolest thing. I looked long and hard for a pattern that had a zipper in the pocket. There were a few patterns that had a hidden open seam in the pocket, which provided plenty of room for entry but they tended to be drafty. Then one day it hit me: The zipper's IN THE POCKET! No one will see it! Who cares what it looks like!
I played with the pocket just a little, came up with a way to stick the zipper in it (no, it doesn't look wonderful, but who cares? For anyone who's curious, I've got a photo album of the process HERE), put a blue zipper on a pair of black pants and never again considered the pattern guide to be The Final Word on how to put a pattern together.
Which I suppose was the foundation for the waaaayyy out of the box thinking I now find myself doing to put costumes together.