The simplest definition I have heard of a bad boy is that he is any guy who is bad for you, period.
The problem is that while a fling with a bad boy can be fun, bad boys are the junk food of a dating world.

Good for a quick bite in a pinch but bad for your long term health.
Here are signs you are dating a bad boy before it's too late

1. He fails to follow through.
He might say that he will call or go out with you but when the time comes, he flakes if you call him out on it.
He is only slightly apologetic or acts like you're the one who is making a big deal out of it.

He often comes up with lame excuses later but somehow manages to make up for it just enough to get you to see him another time.

2. He is a lone wolf.
When you ask about his family, he remains tight - lipped and changes the subject. You haven't met his friends or family and he seems committed to keeping it that way.

3. He keeps you off balance.
One minute you two are having a hot, ridiculously good bad - boy sex and the next, you are wondering if he's disappeared completely.

You can't get a read on what is happening between the two of you at all since there is no identifiable pattern to your interactions.

4. He seems to have a pack of women following him.
Even if you have never seen or met these women, you can just feel it.
When you are around, he seems interested enough in you but something about him gives you that feeling that there are other women waiting in the wings.

He may intentionally give you this impression or it may just be a feeling that you get.

Read number 5 here:-https://www.selfbrandpal.com/2018/07/signs-you-are-dating-bad-boy-number-5.html?m=1

Really ,you must have judged a whole of guys wrongly ,I still fail to disagree with some of them if not all ..