There are quite a few...
Prewash vs not prewashing: Some people don't prewash because they "like the old quilt look" while those who prewash think these non-washers are nuts because of shrinkage, bleeding, and not knowing what's in your fabric and where on earth it has been.
Machine vs hand quilting: Haven't met any on here, but there have been accounts of people who think that if its machine quilted its not a "real quilt". My opinion on that is I hand picked the fabrics, I cut the fabrics by hand, I pinned the pieces together by hand, I pressed the blocks by hand, sandwiched the whole thing by hand (while on my hands and knees on the floor), and still used my hands to run it through the machine.
How to handle a LAQ when they did a crap job on your quilt: Some say demand a refund....and a few suggestions are just short of going back to that quilt shop with a torch and a pitchfork.
Existance of quilt police: Like aliens, most quilters think they don't exist, but a few have said they've made contact with them.