When we incur resistance or even hostility towards the gospel message, there is no reason to automatically think that there was something wrong with our content or our presentation.
Perhaps we were argumentative or came across as frustrated or judgmental that the other person was so moronic that they just can’t figure it out. Those things we certainly need to repent of. However, if we are speaking the truth in love, one’s response is absolutely irrelevant when assessing our faithfulness.
Moreover, how would we know that God is not using his truth to expose the hardness of heart in someone, which perhaps would eventually take them to a place when they will be desperate for the forgiveness of their sins and imputed righteousness found only in Christ?
This is why the whole modern concept of making Jesus attractive to unbelievers is folly and an absolute denial of many biblical teachings. All that proves is that unbelievers are attracted to emotionally-driven music, motivational speaking and other types of entertainment. Secular marketing experts have been capitalizing on those human tendencies for many, many, decades.
Again, the response that appears in Acts 28:24 demonstrates that the unadulterated preaching of the truth of God pierces the heart and the same truth can have a hardening effect on some and a saving effect on others. It is not our job to dictate when and where the Spirit will work, for Jesus said in John 3, the Spirit blows wherever he wishes.
So instead of manipulating and manufacturing perceived results, we are to give the core truths of the gospel indiscriminately.