Jen continued to wear her Mafia blacks, to the detriment of her working wardrobe. She preferred to stick her head in the sand and play the stung victim. Had she taken Irene's words for face value, she would have realised that her friend may have been right. All feedback is good. Those who want to see you fail won't bother to tell you about the little things you're doing that aren't helping your career or relationships.
Companies spend huge fortunes every year to get customer feedback, regardless of industry.
Service and product quality are the driving force behind profit. In order to deliver what the customer wants, the provider needs constant feedback, no matter how awful it is to hear. Knowing what they're doing wrong helps them deliver the customer's perception of value and service. This is a useful way for individuals to think too, so that you can improve your own service and product. This way of thinking can be applied to all types of picky comments people send your way, whether it comes from your boss, customer or interviewer.