The phrase "takes pains with" means to devote time and effort to something in order to do it well. Antonyms or opposites of this phrase include, "rushed through," "slacked off on," "neglected," and "didn't bother with." These antonyms suggest a lack of care, attention, and diligence. When someone takes pains with something, they are careful and conscientious, whereas when they rush through it or neglect it, they are likely to make mistakes or produce work that is incomplete or unsatisfactory. It's important to take pains with tasks that are important to us in order to achieve the best possible outcome.