I try to stress as much as possible for men and women to be careful who they choose to mate with, but no one seems to listen. Once you have a child, you're stuck with their mothers/fathers for life. Yes, your child/children will be “legal” at 18, but there's always the costs of college and whatnot. Pretty much, having a child with someone is a lifetime commitment. That lifetime seems much longer when you guys break up and develop ill will towards each other.
One of the things that grinds my gears about some couples who break up on a bad note, but share a child, is that they bad talk them on their social networks and to their child. No matter how much you bitch about your baby's father/mother, the fact that you chose to swap bodily fluids with them tells more about you than them. Stop bitching about them to your child. That's immature and unfair. Unless they physically abused you or you child, your child has the right to form their own opinion about their parent rather than inherit yours.
In Texas, there is a law regarding this practice, also known as “Parental Alienation Syndrome.” If the custodial parent is infiltrating their child's mind with negative things about the non-custodial parent, there can be legal consequences. I kinda think this should be a worldwide law. This is how resentment and hostility towards fathers and mothers start. A bug is planted and they begin believing it whether it's true or not. If their mom/dad is a hateful twat, their true colors will emerge and the child will make their own decision.
If the child's father/mother isn't treating the child how you think they should, settle it in court and shut the hell up. Geez, have some damn class.