They didn't do it perfectly but they did it perfectly? Do you have two different definitions for "perfect" and are mixing them?
But to avoid any more wordplay: Sometimes you need to use a flawed technique to achieve an end. You can execute that flawed technique perfectly, but that won't make it a perfect job.
There were interesting comments about 'having regrets' previously: https://news.ycombinator.com/item?id=33118584