What is so bad about a frown?
Sorry if the answer is obvious, but it just struck me that I've seen lots of people referring to 'honing out a frown' or even breadknifing the blade to get rid of one, but I don't know why they are so undesirable. If the wear to spine and edge is such that the whole edge still contacts the hone and gets sharpened, what's the issue?
I know that some blades are designed to have a smile and that there are techniques to put a smile on a straight blade, just wondering why not the opposite?