I hear so many people say that the Holy Spirit convicts us of sin.....?

If you read John 16:8-11 it actually says that the Holy Spirit convicts the believer of rightoeusness (i.e. he reminds the believer of his/her righteousness in Christ) and the sin He convicts is actually directed towards unbelievers and that is the sin of unbelief in Jesus. Why do so many people wrongly ume that the Holy Spirit is like a kill-joy policeman constantly pointing the fickled finger ?