You have to understand what the natural link is?
Links Natural links are shared by the common user. Which users usually have the habit often share links as follows:
Just copy the URL in the address bar and then paste it into place to share such as forums, social networking without the Anchor Text as SEOer often do.
Google will rely on this factor will evaluate which links are natural or paid links.
Paid links fool the system to think your website is a quality website with quality content, it creates a situation where non relevant websites appear in the search results and google doesn't like that.
Google doesn't hate paid links. It hates obviously paid links. If you see a site that states: " We are selling links!" you need to avoid at all costs. Most guest posts are also paid links, but if done the right way there will be no G. penalty.
Due to paid links there are few sites which ranks in a matter of few days. So it's kind of black hat which google hates. So google obviously don't encourage such SEO. So in turn they hate paid links...