Double negation expressions like the below ones are confusing to me, but in reality similar sentences are ubiquitous.

> 
> [I don't dislike the police.](https://www.theguardian.com/uk/2008/nov/18/knife-crime-uk-crime)
> 
> 
> 

> 
> [It's not uncommon for parents to know the gender of a baby before
> they enter the delivery room](https://time.com/4353460/enums/)
> 
> 
> 

> 
> [nobody who does not rise early will ever do any good](http://content.time.com/time/magazine/article/0,9171,900640,00.html)
> 
> 
> 

Here's my questions.

1. Does it sound strange when you hear ***I don't hate ...*** instead of ***I don't dislike ...***, ***It's not rare*** instead of ***It's not uncommon***, and ***nobody who rises late ...*** instead of ***nobody who does not rise early...***? Do they make difference?
2. Is there any case that the two negative elements in a double negation sentence cancel out each other and turn out to be a pure positive meaning? e.g. I ***don't dis***agree with that. → I agree with that.