I have to admit it: I was shocked when I heard the news this week that Glen Senk, the widely-admired CEO of Urban Outfitters, was resigning. Sure, the company wasn’t coming off the best of years, having battled lackluster sales throughout much of 2011. A series of fashion misses — nothing new in the always dicey world of women’s apparel — had taken their toll on profit as the retailer sought to clear slow-moving merchandise with deep discounts.