In Retrospect

I shouldn't have let the snake ruin my session. Instead I shoulda just gone for the waves and told him to take his yellow board and bug off!!

More Surf Etiquette
The drop-in happens like this: Surfer A is closest to the curl, paddles into and catches the wave, only to find that Surfer B -- the dropper-in -- has also caught the wave, from further out on the shoulder. Surfer A is then blocked from making a successful ride. The two surfers may collide, accidentally or deliberately, but it's unlikely that either will enjoy the wave to its fullest. At some critical surf spots, Surfers A and/or B may even be placed in physical danger as a result.

A more subtle, yet potentially more offensive form of ride interference is the snake. This move is very bad etiquette, a greedy exploitation of the generally understood drop-in rule, and is usually practiced by competent and aggressive surfers. Snaking works like this: Surfer A, in position and having waited his or her turn, begins to paddle for the wave. Surfer B (the snake) waits until A's focus is purely on catching the wave, then makes a quick move to the inside and takes off, claiming the wave. If both surfers end up riding, it appears A has dropped in and is in the wrong, yet both surfers, and usually most onlookers, know otherwise.