First is the over broad "inch deep, mile wide" approach where too much is expected to be covered within one school year. There is no way to adequately cover all the standards we are expected to teach. Sure, I can introduce and "cover" all of the standards, but teaching and learning are two separate things. One of my mottos is, I measure myself, not by how well I teach, but by how well my students learn." If all I was concerned about was teaching, then it's no problem - I teach and then its done. However, once you take ownership of the responsibility of ensuring that your students actually learn what you teach, then the task grows much larger and consumes much more time.
Second is the cognitive level of some of the topics we are required to teach. In addition to my technology TSA duties for the previous 3 years, I also taught 6th grade math. 6th grade students are in the transitionary cusp that Piaget describes of moving from concrete to abstract thinking. Topics, such as integers and algebraic equations, are so abstract and time consuming that we are forced to give short shrift to one of the most challenging topics that we teach which could be thoroughly covered with concrete, hands-on lessons - fractions. We sacrifice the time that we could use to cover this topic in such a way that they would integrate it thoroughly into their schema in order to teach topics that they are cognitively and developmentally not ready for.
In order to do my best to address this, I use Vygotsky's scaffolding principles of the zone of proximal development trying to bridge that gap between concrete and abstract reasoning by integrating as many hands-on activities and demonstrating all my teaching visually through projecting interactives and demonstrations. The hope is that common core standards will simplify this, but after 72 hours of training on the common core math standards last summer, I am less than optimistic. While the 8 mathematical practices are encouraging in the way they describe math as being taught, there remains still too much required content coverage to be of much help. The jury is still out and we will see what the future holds. Nevertheless, the truly great teachers will continue to make up the gap. As one former employer stated, don't tell me how it can't be done, tell me how it can be done.