There are some good things about Crossfit. For example, it introduces concepts of lifting to the general public. I also pushes the idea of working really hard to achieve your fitness goals. I have done a lot of their Workouts of the Day (WODs) on my own. My perception is that many Crossfit gyms take these readily accessible WODs and make them into very competitive, time-based exercises in high-priced gyms. That is where Crossfit becomes dangerous.  Making people compete with each other to do the most deadlifts or clean and jerks in 10 minutes is asking for someone to get hurt. The culture of the Crossfit gyms seems very variable and often fucked up. Pushing people way beyond what they can do to be "hardcore" gets people hurt. You also shouldn't lift for time IMO.