Think a simple "arrangement" with a friend won't complicate your life? Think again. Adding a physical element to any friendship is guaranteed to cause problems. At least for a short while. Things will likely get complicated very quickly, and these issues can long outlive the friendly affair. So here are 5 reasons to keep your friends and refuse the benefits.

1. It changes your relationship

Duh! When you start sleeping with a friend they're not just a friend anymore. Hanging out platonically gets mixed into hooking up. When are you buddies? When are you more? How should you act around your mutual friends? And better yet, who gets to know about your new liaisons? After all, if you two start keeping secrets from your other chums it sends the message you're doing something unsavory.

2. It complicates dating

What happens if you meet a perfect match and they ask you if you're seeing anyone? How do you respond? "Well, I'm casually sleeping with a friend. But don't worry, you'll meet them soon!" How would you feel if they were in a similar situation? And what if this is typical for them? Being surrounded by people your current beau has previously slept with wouldn't be comfortable for anyone.

3. It increases health risks

Without exclusivity and commitment you're exposing yourself to many more health risks. Casual situations can lead to casual behavior. This can make the seriousness of sex harder to see. Having fun with someone you enjoy can blind you both to consequences and lessen responsibility.

4. It changes feelings

Keep in mind, having a friend with benefits doesn't mean you're dating. Affection and intimacy beyond friendly banter changes your brain and body responses. It's easy for one of you to start having romantic feelings for the other. But not reciprocating those new feelings can cause major chaos in an old friendship. Even if each of you begins to consider dating a real possibility, you may not be as compatible as lovers as you were as friends.

5. It blurs lines with others

Once other people discover your tryst it can give your mutual friends ideas. If you're willing to go there with someone out of the blue, and with no baggage, why wouldn't they try their luck with you? A clear boundary has to be set in place with friends who could harbor potential attraction to each other. Trust must be established and respected. And this assumption is generally made for others in the group. People know how they stack up against each other when jockeying for a more cozy position with a friend. But when someone breaks the assumed rules it creates confusion. You might find a lot more friends crossing the line and trying to get closer to you once they've seen another do it.

"Friends with benefits" almost always gets messy. Whether it ends with a bang or sputters and dies slowly, the aftermath usually isn't worth the risk. So think long and hard before jumping into bed with a friend. You may ruin what you had for only a few nights of fun.