In Chinese, there is a proverbs “海纳百川(all rivers run into sea)” which describes the sea refusing no river. And we use it to describe something can contain lots of different types, and sometimes to describe a person who is magnanimous, tolerant and forgiving.
In my opinion, the sea is really like a person. Beneath the peaceful surface, there is huge number of marine organisms fighting or eating lower organisms of marine food chain. People like covering up emotions they have, and protend to be kind or calm.
The point is interesting, should be considered.