Every parent wants to be their child's best friend, but that's not a parent's main job. Are parents ready to actually be what that word means in every sense?
According to Your-dictionary, a best friend is a person who you value above other friends in your life, someone you have fun with, someone you trust, and someone in whom you can confide in. Now, parents, can you say with confidence that you have this kind of relationship with your child? Can you confidently say that you will be the first person your child will call if something happens to him/her? If yes, then you have the most wonderful relationship with your child and you should keep it up. But if no, you should really try to begin to have that relationship with your child.
I have a problem with parents offering their child a relationship of friendship with statements like: "always come to me if you have any problem" or "you know you can always trust me, I'm your father/mother." However, it is a popular thing for parents to tell their children's business to other people after they have fully trusted enough to want to confide in them. Parents should know that they had a responsibility to their child from the first second they came into the world; which means that no matter what happens they should take that responsibility to actually want to be involved in their child's life. And these responsibilities do not mean just providing for the child with food, clothing and shelter. They should actually make the effort to want to be their child's best friend. Try to be open to whatever your child says without judging, don't bully them into doing what YOU want, rather respect your child's decision and heed them.
Instead of just offering to be your child's best friend and using it to bully them later in their life, put an effort in by actually being their best friend.