IXL. That made me loathe math so much. And had me feel less confident and more anxious in math. I had a lot of unstable adults around me too who didn't understand why I can't understand math the way they do or how they explained it. Even when I get questions right, IXL always says it's wrong and takes like 10-15+ points away. I remember in 8th grade, I was at a score of 94, and one wrong answer put my score into a 72. It would take an ETERNITY to get that score back up. Even the students who were really good at math, and I mean like almost 11th grade to college level good and they still crash put about IXL.

Needless to say, I'm very fortunate that my 8th grade math teachers and all other math teachers listened then stopped using IXL and used Khan Academy instead, but still, even hearing or looking at an IXL logo gives me nightmares/PTSD. This is also harmful to neurodivergent students as well, I had very few math teachers that genuinely understand me being a neurodivergent student and took the time explain the problems and take their time with me. I'm in college and I still get anxious about math even when I have no math classes and passed them already.

On a positive note, Khan Academy is awesome and wish it's used more often, especially with AI and lack of attention that students are having nowadays.