I'm going to leave a coworker out of a group text
Why would you leave her out of the group?
She's a very boring person. I read her texts and she never said anything interesting.
That's quite a petty reason to exclude her from the group. I think you should invite her even if she is boring.
But I don't like her.
I understand, but it's still impolite to leave her out of the group text. Doing so might make you look bad in the eyes of your coworkers. I think you should invite her anyway.