I'm curious whether you think you can maintain that objectivity in the face of things that you find extremely personally repellent. It's one thing to nod acceptingly when the client is describing behavior that's just not your taste; it's quite another to do so when it is behavior that you might regard as pathological but is not causing distress for the client.
For example, among the sexual paraphilias listed in DSM-IV are sexual sadism and sexual masochism. How would you respond to a client - or a couple - who routinely practiced heavy S/M in their sexual relationship but did not feel any distress over it? You might see this as a pathology if you agreed with the DSM-IV evaluation (which I find lacking, BTW), but if the client's complaint does not involve his/her sadomasochistic urges, would you have the will power to let that alone?