Could be just the type of ride you did? I had a pair of shorts last year that were fine for shorter and dry rides, but put them on for a long ride or a wet one and they'd lacerate my poor backside.... something about the stitching on the chamois acted like a little saw blade - left the darndest marks on my hienie - looked like I'd been bitten by a shark and it was none too comfortable either. Slathering the stitching up with chamios butter didn't help either.