Candycane, there's a difference between relaxing properly and relaxing till the hair is bone straight. Most of the time when a professional relaxes the hair (or at least someone who knows what she's doing), it will be relaxed to remove a decent amount of the curl pattern, but not every shred of it. When the right proportion of curl pattern is removed and the correct amount is retained, it's properly relaxed. This is what we all shoot for. If all of the curl pattern is relaxed out, this is bone straight, which reduces elasticity. Reduced elasticity leads to weak, fragile, brittle hair, which causes damage and breakage.