The most common argument about genres comes when discussing popular artists like deadmau5 or Skrillex, who use a lot of different styles of EDM on their tracks. They tend to get defined by their prominent impression (House for deadmau5, Dubstep for Skrillex), but there will always be a pedant pointing out the trance sections of deadmau5 and the progressive house aspect of Skrillex's work. Broad definitions at best, and many artists will fit more than one genre.