I don't think there's such a thing as too sharp. I do think there's such a thing as a blade that requires more concentration than others. Case in point, my Thiers-Issard extra full hollow. If I don't slow down, it will nick me up pretty good. It's the only razor I own that I really need to take my time with. It also gives me the closest shave out of my razors, and without irritation. The reason for both is because the blade is an extra full hollow, or singing blade. The edge flexes and contours to my face a little more than the full hollows. Which accounts for the closer shave and higher chance of nicking myself. So in conclusion, if you take your time, there's no such thing as a too sharp razor.