CSS methodologies and best practices such as CSS Semantics, OOCSS, Grid Systems, SASS, LESS, (and more) exist to guide us towards making more efficient and more maintainable CSS. However some of these tools and ideas have conflicting ideas and when their methodologies are not understood well enough, we can even do more harm with them then without. This talk aims to expose the pros and cons of some of the most widely accepted CSS best practices, which ones contradict others, and which ones compliment others.