Think of the normal beach environment where the water depth goes from shallow to deep as you move away from the beach. As the wave moves into the shallow water, the bottom of the wave is slowed down from the intereaction with the bottom. This is why the waves get higher in the shallow beach areas. Out in the ocean the same amount of water is spread out over a greater area. The waves are longer and lower. When they come into shallower water, they are slowed and build up in height. As the wave moves into even yet shallower water the taller wave begins to lean forward until the top gets ahead of it's base and it topples forward. This is the same procedure seen with the Tsurnami waves that devastated some coastal areas recently. The Tsunami waves are hard to observe and detect out at sea because they are very long in duration and not very high. You can't even sense they are passing. But, when they get into shallower areas the waves grow to be huge.

Ocean Waves Waves are generated by winds that blow over the surface of oceans. In a wave, water travels in loops. But since surface is the area affected, the diameter of the loops decreases with depth. The Diameters of loops at the surface is equal to wave height When waves approach shore, the water depth decreases and the wave will start feeling bottom. Because of friction, the wave velocity (= L/P) decreases, but its period (P) remains the same Thus, the wavelength (L) will decrease. Furthermore, as the wave "feels the bottom", the circular loops of water motion change to elliptical shapes, as loops are deformed by the bottom. As the wavelength (L) shortens, the wave height (h) increases. Eventually the steep front portion of wave cannot support the water as the rear part moves over, and the wave breaks. This results in turbulent water of the surf, where incoming waves meet back flowing water. Everything you wanted to know about waves http://www.earthsci.org/education/teacher/basicgeol/ocean/ocean.html

As they said breakers are due to a sea bed sloping up to a shore. Generally, the longer and more gradual the slope the larger and higher the breakers are. The great surfing areas of the world, California, Hawaii, Australia, South Africa all have similar coasts, long gradual sandy bottoms, with nothing such as off shore islands or reefs to break the power of the waves as they come in from the open sea. The full power of the wave comes roaring in to be tripped up by the sloping bottom. The Atlantic and Gulf coasts of the US are shielded by long narrow low barrier islands, so the waves never make it to shore. There are not even very large breakers on the seaward shore of the islands, there are a series of rows of sub surface sand bars seaward from the islands. When a wave bottom hits the deeper bars it loses some power without really breaking, as it passes over shallower and shallower bars it loses more power until it finally breaks on a bar, losing more power to break on the next bar, and so on until it reaches shore. The waves don't have a chance to build up much height between bars and the larger breakers are on the more seaward bars diminishing as they get closer to shore. Sea waves roll into shore and not away because off shore winds usually can't compete against the power the waves build up over the greater distance of the open sea. In smaller bodies of water, lakes, lagoons, small bays etc. the wind can push waves away from shore. If the bottom slopes and other conditions are right you might see something that could be the opposite of a breaker, (a mender?) as the top of the wave is blown out, water comes 'slopping' in at the bottom and then rolls up and over. Waves moving away from shore also don't break because the bottom slopes away and deeper as the wave moves out, there is nothing to trip its feet, in fact the wave may get higher as it moves out. There is a circumstance where some might say a wave breaks away from shore. On coasts with barrier islands an off shore wind can blow waves out across the narrow shallow lagoon between shore and the island. The wave could break away from the real shore onto the landward side of the island. Of course the wave is breaking *into* the island and the waves aren't very big since the lagoons are so shallow and narrow, and waves are breaking from the sea on the other side of the island.

Most all waves break toward the shore because that is where waves have to break. A wave can travel any direction but eventually it will hit a shore, thus breaking at that shore.

because it looks pretty when it breaks like that, so, that's how God made it!

i first read the q as: why does a linear wave bend in such a way as to be more parallel to the shore? which i don't know if i've seen them do, but in theory they ought same reason a fishtank looks shallower from an angle