Now, from the title you think I want nothing more to do with OC's, but I actually don't have anything against them. OC's are fun and I like seeing how creative people can be with their OC's. Then there's my problem. Mary-sue OC's.
I know you've seen them! who hasn't? they're out there being sueish!
Now, to identify these Mary sues all you have to do is look for some details. It's like saying that an OC  is more powerful than Ben ten and could beat him in a battle. Or, like saying that your OC for example named: Moonlink Prime or something sueish like that can beat Megatron just by looking at him. You know, the OC's that can bend the rules of a show so much just so they look powerful and sexy.
The sexiness is annoying too. When someone has made it that their OC for example has caught the attraction from Rook doesn't make sense. When they say that he's obsessed with that OC it isn't right. When the creator of the OC says that Rook wants to make-out with the OC they are just being retarded because as we all remember Rook doesn't know anything about earthly affection; as shown in predators and prey part 1 where Rook didn't even know what a pat on the back was. Plus, you can't say that your OC makes out with Rook because that's practically mouth rape! He doesn't know what it is so it's not right. I pair Rook with Ben sometimes, but Ben teaches Rook about affection so there's no real problem there and Ben's a real character in the BEN TEN FRANCHISE.
An OC cannot take spotlight as the main character of a show and completely mess everything about it up. It's like saying that an OC for transformers can read minds and kill people just by looking at them, it doesn't make sense!
That and the average mary-sue OC is thin, tall and beautiful. They also catch the eye of every male character, sometimes the female characters as well.
If you're offended by this then I'm sorry. Some people have told me that my characters are Mary-sues, but I like that because then it means I can work on that character and improve them! Like my character Serina for example, I don't say she's the most powerful witch in the whole world. She's clumsy and if she ever tried to fly a broom she'd probably sit on it for 2 hours screaming "WHY ISN'T IT MOVING?!" or something funny like that Don't get upset about it!
I hope you all understand, thank you for taking time to read this.