The answer is simple: guilt. Most women cannot understand why a guy needs an expensive 'stereo', especially since an iPhone can play music. Most men cannot understand why a gal needs so many pairs of expensive shoes, especially those costing over $400 a pair. If you tell a gal the real cost of your stereo, she will be bound to match it in her shoe wardrobe. If you were smart, you would insisted that one of her wedding vows would be to never question your spending on your 'stereo'.