[JAGG]

Anger management issues should be a red flag. Getting inappropriately angered over a minor situation, and or not being able to wait for a proper time to discuss things. Lashing out in a public manner would be a huge red flag to me. They don't seem to care that God and everyone with in a 20 mile raduis knows they are angry. They take their anger out by doing things like drive way too fast and cut people off. There is a time and place for everything, if they can't wait for the proper time and place that should be a red flag.
They have intitlement issues. If they are wronged in some way they want to even the score. They are vengeful. Even in small matters. Someone doesn't take off fast enough when a red light turns green so they fly around them and then slam on their brakes when they get in front of that person just to "teach them a lesson".

The way they treat strangers and the way they treat anyone, is eventually the way they will treat you.
How many close friends do they have? How many long term friends do they have? If the answer is none or very few you have to ask yourself why is that?
If they are not close with their family on top of having little to no friends you have to wonder why. Now I know some families really suck and are disfunctional beyond repair, but you can't over look the fact that they have no contact with family and very few friends.
If they are what is called a job hopper. Can't keep a job for very long . Has been fired a lot from jobs. You have to wonder why. It can't always be everyone elses fault.
They try to keep you away from your friends and family. Or come up with reasons why they don't like this friend or that friend and don't you to be around them. You are both adults and as an adult you have to learn to get along with others . The better you can get along with people even ones that irritate you, the more successful you will be in life. As adults we don't cut people out of our lives because someone decided they don't want you around someone.You end a friendship or severe ties with a loved one because you decided that person is not good for you someone else doesn't get to decide that. And you picked these friends long before they came along they don't have the right to decide who gets to be your friend and who doesn't. But you have the right to decide that they need to pick a new girlfriend.
If someone makes a statement like, I am not relationship material, or you don't want to be in a relationship with me, I'm too this or too that. Believe them !!! And run right then!!! DO NOT ASK WHY and don't think you want to prove them wrong by trying. JUST RUN !!! Trust the universe did you a favor and count your blessing every step you take in the opposite direction.

Okay I hope that helped a little . I am sure I will think of more and post again later. I am not an expert by any stretch and I have never been in an abusive relationship, I have been blessed to have had many wonderful femmes in my life, a few bad apples too but never abusive. But I have seen many friends of mine, go through things, so these are a few mental notes I have taken through the years.