Even though it's only a difference of 15 minutes, it's easy to cause a fight. When you're waiting for your child to be dropped off, you're irritated that your ex is late and that it's cutting into your time. When you're waiting for your ex to pick up your child, those late minutes can cut into the plans you had, and make your child upset.

You want your kid to enjoy their toys no matter whose house they're at, but when the other parent doesn't keep up with the stuffed animal they need to get to sleep, things get super tense.

Nothing gets people more upset than talking about the holidays. Both of you want to die at the thought of not seeing your little one on Christmas, but you know it's not fair to get all of the holidays. Lots of emotions which means lots of drama.

Often, the non-custodial parent can fall into the "fun" parent category. And I get it. When you only see your little one a few times a month, you want them to have a blast with you. You're not responsible for getting them off to school or doing projects, so why can't you be the fun parent? Because it makes your ex feel like a total jerk and your kids feel like their other parent is always on their case, but you're not.

You drop your kid off with your ex, and when they come home, they're talking back, being rude, and a total handful. You're quick to blame your ex because, obviously, it's all their fault.

"I sent her to your house in brand new tennis shoes. Where are they?"

"I have no idea. Ask her."

"She said she left them at your house."

"Well they aren't here."

Ugh. Nothing more frustrating.

This happens to the best of us, but it's really bad in a co-parenting relationship. When your ex won't answer your calls or reply to your emails, it's hard to keep a cool head. Especially if it's something pertaining to your child.

Whether it's a fight over completing homework the way you do at your house, or simply making sure your ex sits down with your child to do it, the homework battle is huge. It's also a hard subject for co-parents because you want to be involved in every aspect of your child's life, so not knowing what they had to do for homework can be difficult.

You never got along with your ex's mother and now your kid sees her every other weekend. People get very defensive about their families, and this can cause some big fights between co-parents. You don't want to deny your child their family, but you also want to be included in the role their extended family is going to play in their life, including stepparents. You need to know that you can communicate with them, and that they aren't going to let the divorce/split cloud their judgment when they are with your child.

You demand that your child keeps a clean room, but your ex doesn't care. Your ex makes your child eat everything on their plate, but you don't care as long as they try new foods. These rules may not seem like game-changers, but when the difference is noticeable to your child and their behavior changes, it can cause a lot of grief. Especially if your rules, like wearing a helmet while riding their bike, affects their safety.

Sometimes these fights about school involvement can manifest in two ways — one of you is upset that you're not more involved, or one of you is upset that you can't get the other parent involved. Either way, school is a huge part of your kid's life and it can cause tension.

No one is ever happy. Even when you agree to find neutral ground, someone is always irritated that they had to sit in traffic, or that the location is a mile closer to your house than theirs. Petty, but it happens.

Your child messed up at their other parent's house, and they were grounded for a week. But now they'll be at your house and you had plans to take them to Disney World. This fight happens often and can be fixed with a lot of communication, but it still makes the other parent feel like their words and punishments don't matter.

In general, you may have some different parenting ideas than your partner. Maybe you're hoping to homeschool, but your ex-partner wants them in public education. Or you don't want to use time-out as a punishment, and their other parent thinks it's the best thing for them. Co-parenting means figuring it out together, but it's hard to do when you both think your way is best for your child.

This just causes all kinds of fights. Giving up control is hard, especially when it involves your child. You have no way of knowing exactly what happens when your child isn't with you, and you have to trust your ex the best way you can. Extremely difficult and it leaves plenty of room for arguments.