As I said you really don't know much about all this do you. What you do is important to Christians because we may not like what you do, may not believe your choices are moral, ethical, or correct, and that they are bad for people both you and others who they effect. We are taught to love people, not what they do but the people but we are not taught to love those who commit sin and turn from Christ knowingly. We are taught to pray for them and pray they will turn to Christ. It is a concern of Christians.
I didn't say you were obligated to do anything, that's called freedom of choice and free will which God has given everyone. You will be judged for what you do and how you act on earth because that's what people do, but ultimately God will judge you and if you have never accepted Christ then you will pay for that choice.
Now if you don't believe in God, Christ as the savior, sin and repentance and salvation then you will not care. Ok, so if you are correct you can have a good ole time committing all the atrocities you like, killing babies being among the worst, all the sinful acts you want, you know the ones Christians disagree with. But if Christians are right, you will spend eternity in hell.