Repeating your keywords in an unnatural way is not good for your users and often results in a lower - not higher, ranking in Google.
Webpages are often filled with repetitive usage of keywords, this is called "keyword stuffing". This method no longer works, but people still try it.
The main reason to not use this method is because the use of such language is not useful to your users. Nobody wants to read a paragraph of text using the same words over and over unnaturally. The main reason most people have stopped using keyword stuffing is because it doesn't help you rank in Google anymore.
Some webmasters may wonder how much to use their keywords because another Google webmaster guideline seems to state that we should use keywords - Think about the words users would type to find your pages, and make sure that your site actually includes those words within it.
You are using keywords too much when you are repeating them so many times that your text seems unnatural. If you are a business, you probably do not answer questions with language like "Yes, we do have red widgets and our widgets are red and they are widgets and the other red widgets are not as good as our red widgets because widgets in general are red and our widgets are red too".
If you spoke like that people would think you were crazy and would probably seek another place to get their answers. This is exactly why your should not keyword stuff your pages you sound crazy when you do and your webpage users will go somewhere else.
Remember that your webpage is a way to communicate with potential customers, so clear communication and word usage is important on your webpages so your potential customers know what you are offering and trust you as a resource. If the text you use on your webpage seems spammy or unnatural people will go find a better resource for their needs.
Google has provided these as examples of keyword stuffing