I've picked up some luxury fabrics (Albini, VBC, Loro Piana Minnis, etc) when I wouldn't have on sale, especially the first release and Black Friday things. It's also gotten me to try out some new patterns that I wouldn't necessarily have tried at full price. Got my first polo and popovers done on sale, and had ordered several more since at full price.
I've definitely ordered something and then had it go on sale before I received it. That's always fun.