John said it best, he aid clearly and he said it concisely:
11Beloved, do not imitate what is evil, but what is good. He who does good is of God, but he who does evil has not seen God.(3rd John)
This applies to all areas of life including church worship, sermons, Sunday School teaching and interacting with fellow believers and visitors and so on. We are called to be different not copiers of the secular world which is in need of a Savior. We have found the Savior now we need to act and live like it.