I have a tuck of Shark blades, never tried them as the reviews were so bad. Threw out the Derby blades and some other off brands. Most likely a dud blade to rip you up but if quality control is that bad why bother? I use GSB and get dud blades and just toss them right away. If the blade tugs or feels rough just stop the shave right then. I have several razors loaded and if one fails to perform well right away, it gets put aside and blade chucked. A new razor usually improves things.