It takes only a liitle yeast to affect a whole batch of dough. In the same way a small amount of evil can affect a large group of people. Becareful in thingking "how can this little wrong possible affect anyone? It's a bit like the serpent in the garden of eden convincing Eve that in eating a little fruit her eyes will be opened. The serpent knew this small thing would change their world. There are many books to read and many things to watch--beware what you allow in your mind. In today's world a teenage boy has said he was enticed by his mother's catalogue into the world of pornography. What you see as a little unnimportant thing may no longer be so. In today's world our children are being led to read and watch things which in essence just takes away their innocence. And some of the things that entices them are in magazines and catalogues. Let us be vigilant in doing what we can to help them. It starts with praying to Almighty God for help in wisdom and discernment in everything. The Bible is our greatest tool if we read it and lean not on our own understanding. After all, Jesus gave us an example of how to battle against the enemy when He went out in the desert as He said in Matthew 4:4
It is written"Man does not live on bread alone, but on every word that comes from the mouth of God."