It is good to speak in tongues, whatever the tongue may be, a prayer language, a tongue not known by men, prophecy, interpretation etc...GRANTED it is truly of the Holy Spirit and not something else. How do you know the difference for SURE? Well, that is entirely hinged upon your heart and which S(s)pirit you are connected to. There is no praying in tongues "wrong" or accidentally to Satan, IF in your heart of hearts you are worshiping the Spirit of God. But many Christians are deceived and let their heart LIE to them. These foolish Christians chase after sensationalism, feelings and what appears spiritual before MEN. They want to impress others with their spirituality and have a spirit of manipulation and are also manipulated. The important thing is to be VERY serious to check your own heart and make sure that you are actually going after the Holy Spirit, not something else. Be honest with yourself and be honest with God.