Imagine a mathematics classroom in which students engage in sharing ideas and reasoning through solutions to interesting mathematical problems. They are excited about mathematics and working on challenging problems that encourage collaboration and critical thinking. These are things that teachers want, but sometimes they do not know how to achieve such goals within the constraints of limited time, students' lack of experience, and the pressures of standards. In this article, the authors address one of the Common Core's Standards for Mathematical Practice (SMP), "Make sense of problems and persevere in solving them," identifying resources to implement it, common misunderstandings of it, and associated challenges.