1. They move too fast

People always say "when you know, you know," but it's important not to rush into anything too quickly, or to at least be cautious when you do.

2. All of their exes are "crazy"

If all of their exes are "crazy" and they constantly vilify their exes, there's more than likely a cycle. This person might be resentful and unable to forgive. Be careful, or you could be the next "crazy ex."

3. They wallow in self-pity

If you notice early on your crush hyper-focuses on all of life's misfortunes, this could overflow into your relationship and eventually he will start hyper-focusing on all of your mistakes—big or small.

4. They are self-absorbed

Being self-absorbed can be mistaken for confidence at first, but be careful, too much confidence can be a sign of narcissism.

5. They insist on knowing details you're uncomfortable sharing

If someone pushes to know things about your past that you aren't ready or willing to share this could mean your crush doesn't and won't respect any boundaries you may set in the future.

6. They don't have a desire to befriend your friends or family

If someone doesn't want to get to know your friends or family then this person will more than likely cause you to isolate yourself from them later in your relationship's future.

7. They sneak into your phone or social medias

This invasion of privacy is a huge red flag. Whether it's rooted in lack of trust or in the need to know your every move, it is a huge "no no." This means your crush doesn't trust you and trust is the foundation of any good relationship, this is also a huge sign of controlling behavior.

8. They sleep a lot

The occasional nap is no crime—I should know, but sleeping through work or taking naps every day shouldn't be ignored. If someone sleeps so much it is affecting their day to day, then odds are this person is struggling with things not even love can fix. Just remember it isn't your job to fix someone, and you can only help those who want help.

9. They have no drive

If you notice your crush has no life goals and relies on their parents for everything, then odds are this person is not only lazy but entitled with no work ethic. Unless you want a boyfriend who doubles as a kid, then run away cause you can't file "bum boyfriend" as a dependent for your taxes.

10. They're overly insecure

If you constantly have to reassure someone it can become tiring. This could be rooted in self-hatred and nothing you say or do can make this person believe you care. This can be draining and eventually make you feel like you're not enough.

11. They have double standards

If your crush gets jealous when you go to the gym in a tank top but spends his Thursday nights at Hooters, then you are experiencing a double standard. This double standard won't stop there, later in the relationship you will have all these rules that he doesn't have to abide by—and that's unhealthy, controlling and manipulative behavior.

12. Nothing is their fault

If your crush can do no wrong then you should start to worry. Being able to admit to one's faults is important and admirable.

13. Refuse to make things public

If your crush is adamant on keeping things "just between the two of us," then odds are he has commitment issues, and if he ever does commit you might be left with the feeling that you aren't enough.

14. Conversations seem shallow

If your conversations lack depth than that might mean your crush is emotionally closed off or just plain shallow. Either way, if you can't have a conversation with meaning the relationship probably isn't headed on the right track—or a meaningful track.

15. Taking forever to respond

If he responds every three hours even if he isn't at work and has nothing to do then he's probably just keeping you on a hook reeling every so often just to keep you around. He's probably not interested in you and only interested in what you can do for him.

16. Isolating you from others

Isolation is a huge red flag. If someone causes you to isolate yourself from the people and things you love the most then you might begin losing yourself. People who do this want control. Don't give it to them.

17. Hung up on an ex

If your crush is still heartbroken over an ex then he probably isn't ready for anything serious. But if they broke up over a year ago then this guy either has a weird obsession or is using his heartbreak as a way for attention. Either way, it's a no go.

18. Lacks appreciation

You could hang the moon and this guy still won't say thank you. Be sure that your crush is appreciative of even the smallest things you do. If not, then nothing you do will never be enough and you will lose yourself trying.