When we go to websites that have generated certificates themselves you see this red screen that says do not go there!: example http://www.sslshopper.com/assets/images/chrome-beta-ssl-2.png

However when it is trusted by some companies it's all good. So I have a couple of questions:

• Are certificates that are generated by these companies somehow better/different?

• If we take to account that NSA, for example, has every private key of these issuers doesn't it make private certificates actually more secure?