The best way to serve God is to serve Him in truth. When we serve God in truth, we will not follow sentiments that are generated by human instincts and feelings. Our righteousness must surpass that of the Pharisees as our Lord Jesus Christ told us. The Pharisees in this context means that we should not be hypocritical in our relationship with God. We should be truthful about our walk with God.
Watching movies is not a sin. The Bible does not tell us that we should not watch movies. I have heard of churches where the members were restricted from watching television and movies. They claimed that watching television will make them end up in hell. They taught that television and movies are worldly pleasures. So, members watching those kinds of things would make themselves lovers of the world.
It is true that we should not love the world. The Bible says that those who love the world do not have the love of the Father in them. We are not to be mindful of the things of the world. But does this mean that we will not be acquainted with the events happening around us. Should we not eat food again? Should we not wear clothes again? No! All these are not the implications of not loving the world. We can watch movies.
The thing that we should be mindful of is to be careful of what we are watching. Watching sinful contents is a sin. Let us keep away from the things that are sinful.