Beyond just the sport of surfing, it's also used metaphorically for a 'spirit of challenge' or 'riding the wave.' You can use it when starting a new project or coolly accomplishing a difficult task.

It's sometimes seen as a symbol of surf culture, like in California or Hawaii. As surfing gains popularity in places like Yangyang and Busan in Korea, it often appears when showing off a 'hip' summer hobby. It can also be used to send a positive message of encouragement, like coolly overcoming life's waves.