By Extreme low calorie, i mean what i think nutrition people call "Very Low calorie" diets, which is around 500-1000 cals/day. They are well known to nutritionists as an unhealthy way to lose weight for a variety of reasons.

I tried it without researching or even knowing what it was...because logically I just went "Calories = weight, therefore eat less calories for lower weight, and then GO BIG OR GO HOME!!!"

Im not sure what you mean about frustration. I want to say that anger resulting from frustration is actually resulting from something else though. Dealing with difficult situations might make you miss a meal, become overly stressed, or just be physically worn out and those could all lead to anger imo. However, there certainly is also a psychological aspect concerning failing to do what you think you are able to. Idk how that fits in, but i can certainly see it