Added 12 minutes later
In the mountains, it's actually quite convenient to walk – unless you specifically try to climb to the very top. In the plains, the grass is waist-high, there's a lot of undergrowth, and in rainy weather, there's mud up to your ankles. In the forests, there are incredibly dense thickets, bears roam around, and it's easy to get lost. But in the mountains, there's always solid ground under your feet, you can see everything around you, and it's bright and clean. Perhaps, people like mountains for that reason.
And living permanently in mountainous areas, not in a city apartment, is a complete nightmare even without the need to manage a household.