some people have deliberately violated their consciences
I’m sure you have at different times been offered advice; maybe you set out asking for advice, or perhaps it came unsolicited and somewhat hard to take aboard. Your conscience is rather like unasked for advice; you have got it whether you like it or not, but it is up to you what you do with it.
My mind goes back to this story of Pilate with Jesus on trial in front of him. His conscience told him that Jesus was innocent, and he made moves to release him. And then his wife sent him a message (Matthew 27:19) reinforcing his conscience-message about Jesus’ innocence. But Pilate was a frightened man so he chose to ignore both his conscience and his wife’s conscience-stricken plea. He deliberately violated his conscience and so he made the decision to hand Jesus over to be crucified. A bad decision of course and one which would have further damaged his ability to listen to his conscience in future years. Whether or not he eventually regretted that decision we shall never know but it was another touch of the hot iron that rendered his conscience less sensitive in the future.
A sensitive conscience is a precious asset. That does not mean you go about with a long face, looking for reasons why your every decision might be a wrong one! It is possible to be wrongly sensitive and see problems where none exist, but a conscience can be trained. (You might like to think how that can happen. I personally feel it is through filling our thoughts and desires with what God says to us about holy living in the scriptures. This training helps us to understand and be motivated by what God has declared to be right in His sight.) Such training of our consciences is a long-term business, but is well-worth the determined effort.