"Francois's father does that" and: "Gerda's mother would never do that," are things that every parent has surely heard from their children. That's usually the reaction you get when setting boundaries in your home. That's when you must kick in your heels and take a firm stand.
When you look at parental homes, it absolutely seems as if many parents have become a fearful generation; afraid to set clear boundaries within which their children can move freely and safely. What children (and some parents) don't know is that children actually crave boundaries and want them precisely because it makes them feel safe, and shows dad and mom care.
It stands to reason that your children are going to rebel and test your boundaries. It would be abnormal if your children always say yes and amen to every boundary you establish. Of course, they can say how they feel about it - negative or positive. However, deep inside they know that dad and mom care. Just don't start trembling and give in. That's when manipulation starts and it's very difficult to get out of that web of manipulation.
My wife and I often heard: "Why dad?" Or "Why mom?" My answer was consistently simple: "My child, because I care enough about you and love you enough to set the boundary." There may not be immediate understanding and acceptance, but for the time being your child has plenty to think about.
It’s a very good principle to negotiate boundaries with your children. Take care not to ever be too autocratic and harsh. For example, create certain imaginary situations and ask them what the result should be in such a situation. It’s vital to remember that children accept boundaries much easier when there’s a good relationship between parent and child. So, first work on a relationship with your child before trying to set harsh boundaries.
Proverbs 19:18 says it so beautifully:
Discipline your children, for in that there is hope; do not be a willing party to their death – NIV