The side facing us has the Seas.
The side facing away from us has no seas and tons o’craters.
How come?
Did Earth’s tidal pull on the Moon increase lava flows to make the seas? Did Earth shelter Earththside from meteors? Or did the lava flows that made the Seas cover over the craters onEarthside?
Craters are caused by junk hitting the moon from space. If something is coming from the other side of the moon (in the direction of the earth/moon system), there’s nothing preventing it from hitting the moon. But many things coming from this side of the moon will be drawn into the earth’s gravitational field instead.
The reason for the difference in the two hemispheres of the moon isn’t fully understood yet. The shielding effect of the earth panache45 mentioned is probably a factor. Another possible factor is a higher concentration of heat producing elements on the near side of the moon, which has been observed by lunar probes like the Lunar Prospector. There may be other factors like the thickness of the lunar crust, though the previously mentioned probes found that there is an area of thin crust on the far side of the moon that you’d expect to have lunar seas in it, and it doesn’t.
So basically, scientists are still trying to work it out.
The moon may have been flipped 180° 3.9G years ago by an asteroid strike.
An update: Scientists have advanced a new theory - that the Earth once had a second, smaller moon which gradually collided with the Moon’s far side, creating the craters, which in turn displaced magma flows on the near side, creating the Seas.