Kayaks have the speed to catch waves early, while they are still steepening, and be on a wave before a surfer can drop in. This can be a problem, as the board surfers wait impatiently for a wave, only to see a goober in a kayak hopelessly out of control side surfing toward them. Not only have they lost the wave, they must avoid the kayaker who may have no idea they're even there. This is worse if it's a sea kayak that is prone to broaching and cuts a wide swath down the face of the wave. Don't drop in on surfers, board or kayak.
Surfers actually line up and take turns grabbing waves at the break.
Kayakers routinely take off away from the break on a building wave while a surf boarder is working across the peeling face, only to encounter a kayak that's either stuck sideways or surfing straight ahead. Be extra courteous around surfers. Take some time to size up the situation. If it's the only spot, wait your turn. Sometimes I'll sit a bit in shore from the surfers and grab waves they miss.