Sorry to hear about all of your messes. I have fortunately only had positive experiences with DB. I'll admit there was one time where I didn't receive much help, but I was also just a walk-in and there were already large parties there.
I was supposed to be in a wedding in 2006, bought my dress at the South Bend, IN store, and then the wedding fell through. Well, the receipts say, "NO REFUNDS OF ANY KIND," but a year later I went wedding gown shopping for myself, and figured I would try to return the bridesmaid gown anyways. I didn't go through any hassle at all, and they gave me store credit. I'd had an appointment scheduled, and I got right in. The girl who helped me was wonderful and funny. She offered tips, but didn't push me into anything. She also stayed and worked with me after her shift was through because I was still deciding. And honestly, though this may have annoyed some brides, I wasn't bothered when she excused herself to help another young girl try on a dress or two who had come by herself with no appointment made. I honestly found that very considerate of her. The sales lady gave me a $50 off coupon too- she said they were only allowed a certain number of those coupons each month and they were to be given out using discretion.
Not to be snooty, but maybe it has to do with customers' attitudes?