I developed a hatred for my MIL ever since the birth of my son. Nothing good comes out from her mouth as Chinese believes that we should say the negative to kids so they will grow to be the opposite of the meaning. For example telling the baby he is so skinny, he has no hair, he is naughty etc just so that they will turn out the opposite. I am not a believer of such myths. Ever since then (during the confinement period), I started to avoid her and have not greeted her or talk to her since. It has been 3 years but each time I think about the episode, I just feel very angry and my heart boils. How can I get pass myself so that I can start talking to her again just like before?

I think it might be tough if she is still making those negative comments. As much as you may want to get over the issue, your negative impression of her will be reinforced every time she makes a negative comment. While it is not the best scenario, it may still be better than worsening the situation if there is some sort of balance right now. If there is a chance that one day she sensed your negative feelings towards her and wishes to address it. Then it may be a good time to have an honest talk. Most importantly, either party must be prepared to change (either her changing her behavior, or you changing your opinion of her) in order for the main issue to be properly addressed.