They say that hindsight is 20/20. But sometimes, the reality is 20/20 too. At times, we choose to blind ourselves in the moment to avoid looking at the real cracks and the red flags in our relationships. We make excuses for our partners - we tell ourselves he didn't text us for days because he was just busy, or that he's controlling because he loves us, or that when he texts, "you up?" he really means "you're beautiful," even though we know exactly what he meant.

The expression, “if it looks like a duck and walks like a duck, then it’s probably a duck” applies to f*ckboys too. Hopefully, we can identify these ducks before they walk all over us.

1. The one you never see before the sun's down.

You come to realize that the only time you and this guy ever hang out is after a certain time of night, and he makes minimal effort to see you or talk to you during the day. He'll text you really late, and send you those classic "You up?" texts. As much as you don't want to admit it, you know his intentions are probably sketchy, and he's probably not the type of guy you want to go to brunch with the next day.

2. The one who constantly flakes.

We've all had to cancel or reschedule a date for a good reason. But you know the difference between a real emergency and a flake. He's always flaking on you, always rescheduling dates, because he thinks you'll always be available for him next time around.

3. The guy who is rude to your friends and family.

MAJOR Red Flag. If he doesn't make the effort to be nice to your friends and your family, does he really value you?

4. The one who cheats.

He says he won't do it again, but...

5. The one who calls all his exes "crazy".

It's okay if you've gone out with a couple of crazies (we've all been there). But there are those guys that call every girl they've ever gone out with crazy until you start to wonder: are they crazy, or is he?

6. The one who is still hung up on his ex.

There's a difference between someone being friends with their ex, and someone who can't stop talking about their ex, can't let go and move on. Maybe they even still talk to their ex, which tends to be a bad sign. How can you be with someone who still is lugging their past around?

7. The drunk.

Sure, the party guy is fun to go out with. But he becomes hard to handle when he's getting absolutely wasted every weekend. Once he starts to cross that line from the "social drinker" into the "alcoholic" zone, it can get messy.

8. The one who is a control freak.

He has opinions on everything - from what you should wear, to what friends you should hang out with, to what you should order at dinner. He may even order for you.

9. The one who takes FOREVER to respond.

Maybe he's in a meeting or in class or is really busy. But when he's taking hours and days to reply to a text, you've got to evaluate whether he is a horrible texter or he's just not that into you.

10. The one who won't commit.

He might be upfront and say that he has commitment issues or might avoid any discussion about what you two are or where you two are going. He may have real issues he's working through - or he might just not be ready to stop sleeping with other girls. He's usually a waste of time.