For instance, the rosary. Jesus tells us in Matthew 6:7-8 "But when ye pray, use not vain repititions as the heathen do for they think that they shall be heard for their much speaking. Be not ye therefore like unto them for your Father knoweth what things ye have need of, before ye ask him." God seeks heartfelt, meaningful prayer from us, not simple repitition of a few words over and over again. Jesus' words make that clear, therefore saying the rosary is obviously something Jesus doesn't want people to do, and is therefore sinful to do. Does the word "vain" mean anything?
You apparently have no understanding of contemplative prayer and a great desire to judge others.
SD
John 12:48-50 - And if any man hear my words, and believe not, I judge him not: for I came not to judge the world, but to save the world. He that rejecteth me, and receiveth not my words, hath one that judgeth him: the word that I have spoken, the same shall judge him in the last day. For I have not spoken of myself; but the Father which sent me, he gave me a commandment, what I should say, and what I should speak. And I know that his commandment is life everlasting: whatsoever I speak therefore, even as the Father said unto me, so I speak.
I'm not doing any judging - Jesus' word will do that, as he stated in the above verse. The word that he spoke in Matthew 6:7 was from the Father, therefore I receive and embrace that word so that I will not be judged by it in the last day.