Oh lets see...
1. They park outside your house and watch it for hours 'because they are concerned about your safety'.
2. They steal from you.
3. They vanish for hours at a time, every time they go to the gas station around the corner.
4. They try to come in and take charge of your life, because, you know, they're trying to help and you're clearly the jerk who won't let people in if you say no thank you.
5. They keep their phone locked and want access to yours.
6. They also hack into your email account.
7. They don't want you to meet their friends and on the rare occasion you do meet some of them, the friends are surprised to discover that your partner isn't single.
8. They think roses are the perfect apology for when they scream at you, hit you, or throw things at you and you are the jerk if you don't swoon over the obviously grand gesture and kiss their backside for the next week.
9. They start talking about how it will be when 'we're living together' even though you've only been involved for a week or two.
10. The second time you get together/chill/talk/whatever, they start screaming about how much they hate their ex and want to kill them.
11. The only place they trust you to be alone (meaning without them) is to their mother's house. And they will drop you off and pick you up.
12. They tell you how you are perfect, perfect for them, and how you are the only one in the world who can make them into the better person they know they are, deep down inside.
13. Even after the billionth time you tell them you aren't interested, they still keep asking if you are yet and when all that will change because you know, you are obviously so perfect for each other.
14. They lie all the time about the most ridiculous crap.
15. When you get upset, they either turn it back on you or distract with irrelevant stuff that leads so far from the original issue that they can then pretend that the original topic never existed.
16. When you get upset, they freak out and start flailing, and screaming that they need a pastor.
17. They underline bible quotes that carry on about how women should submit to their men.
18. They tell you everything you do is going to make you go to hell, including pinstripe dress pants you own for work.
19. I'm out of red flags but wanted to get to number 20.
20. I made it to number 20.