It is said that you surf "Backside" when moving back onto a wave.
It is said that you surf "Frontside" when facing the wave.
The surfers generally prefers surfing frontside because surfing onto the wave is easier
in this position.
For example, a Regular surfer will use frontside and will therefore surf on the wave at
the frontline, if a wave runs from it's peak to the right. And vice versa for a Goofy
foot surfer.