Why are we surrounded by round things?

Hi again, as you dfinietly know today is π day. It isn't so popular in Poland, because here we write date in different way, so today in Poland is 14.03.2018, despite this I've celebrated it, and it made me to some thoughts, that I want to share with you.
We can see so many rounded shapes in many places, for example at websites (profile pictures, logos, fonts), in architure, and also in nature.
it's moon, example of round natural object

why aren't they sharp ended?

I was wondering why round objects are so beautiful for people? and I figured out simple answer, I think that it came from human's nature that is formed by evolution: sharp shapes like sharp stones, thorns of plants, moutains, cliffs and animal's teeth could make you feel pain, bleed and die :c
steep slopes are good place for mountain goats and skiers, not for primitive man. photo from my winter holidays in Alps

So rounded shapes as opposite to it could be associated with calmness , safety and pleasure, ant this have reflection nowadays: most of childlish cartoons are full of rounded shapes, most of children's toys are rounded to be safer and more attractive to them.For more, round shapes are the simplest shapes in the world, and people value simplicity, because we are lazy by nature.
Summarizing, I think the main reason why people like round shapes is natural threats and adaptation, evolution.

I hope you enjoy it,I expect it isn't revealing, but it's interesting for me, you can tell me if it convinced you or not.
Makary