Many Christians have a wrong interpretation of 1 Corinthians 9:22. Paul would not have gotten a tattoo, a Mohawk, piercings etc. to witness to a group like that because it would have hindered him in witnessing to other groups. He spoke to them from their frame of reference, like all great teachers, taking them from the known to the unknown but he did not take on their customs and affectations.
When I hear stuff like "I'm getting a tattoo and piercings to witness to the Goth/Heavy Metal people!" I just shake my head and wonder where in the world did some of our teachers get such concepts to get kids in such a mess. 2 Corinthians 6:17 says we come out and be separate calling them to us not meandering about in their muck and mire. Separation is still a biblical truth. It is time that the Church return to that practice.