My horse chex is always really angry, by that i mean that whenever I look into her stall she pins her ears and flashes her teeth at me. I did just get her in November last year so I dont know her that well, but do you have any ideas why she does this?
Is it just you or is she violent with everyone? Does she have any sort of abusive past? I would call a vet and check for ulcers. Check her teeth. Something is making her extremely uncomfortable. Horses are not angry by nature. If it only happens while she's in a stall, work with her (outside of a stall at first) with her allowing you to come into her space. If you can't find anything to make her more comfortable and it only occurs in a stall, I would look into pasture board or a situation where you can stall her as little as possible. I know several horses that are just not happy being stalled.
That being said, we found out recently that Jamie, my app, used to be so violent that she was almost sent to slaughter. She would turn around, aim, and try to kick little girls at the 4H camp they sent her too when they entered her stall. We heard whispers about men who would go in her stall and beat her with pitchforks because she was violent. She was ridden into the ground. Getting her in a home with love and spending time just hanging out with her, treating her, just spending bonding time with her was all she needed. We made some tack changes (no bit and nothing attached to her head besides a bridle), adjusted to her, and she came right around and became a wonderful horse. If abuse was a possibility for her, I'd prescribe some love. A bit of liberty work can be very helpful for retraining her brain from "humans are bad" to "humans are good."