For instance, in this picture ([url=][/url]). The front of the wave is at 0 phase and travels like that  with the rest of the profile in the x-direction. I know that E&M waves do not necessarily need to start with 0 phase like mechanical waves, but this picture explains how I pictured the E&M waves to travel. The movement of the rest of your profile follows this behavior, it is just the very front of the wave (where it is oscillating the phase it is in) is confusing me. Thank you for helping me understand.