system
Given the following post, respond as if you're commenting on Reddit:
human
[ASOIAF] Why the wall is so damn high?
gpt
Here is a little-known fact about the cold wastes. In the summer the bugs are **horrendous**

Ever been to alaska? The mosquitos don't bite you, they carry you off and eat you in their lair. Its a bird: Its a Plane: Oh fuck, nevermind, its a mosquito. 

So Bran the Builder goes up north to build this wall. He knows he can keep people out by just having it 30 feet tall, he can keep giants out by making it 50 feet tall. So he gets to work making, just to be safe, a 60 foot wall. But then spring starts to hit, a relief for him and his workers until the bugs come. So many mosquitos. At this point Bran the Builder knows what he must do. 

"We must protect our blood and kin to the south. We must ensure their safety and the safety of our future-born. We must keep the bugs out. Build it as tall as you can, then no more will we have to deal with the biting menace."

And thusly the wall became 300 feet tall. Never underestimate a man's hatred for bugs.