A nice, well-designed bathroom can add value to a home. Joseph Hendrickson/ShutterstockI'm an interior designer, and I've seen many bathroom remodels go wrong due to avoidable mistakes.Lack of storage, wrong material choices, insufficient lighting, and bad layout are common issues.By planning ahead and prioritizing functionality, you can create a beautiful and practical space.Redoing a bathroom is an exciting project, but it's easy to make poor decisions that can cost you time, money, and peace.