Okay. I am not Jewish at all, but I follow the 7 Noahide laws.. my question comes why do some Jewish converts or people that are going through conversion, seem way way over the top and way too fanatic than lets say a Jewish person or example even a Rabbi?
I think that any area that is new, a person can become excited.
That being said I think there is a spiritual flaw/benefit that can be involved as follows:
Evening prayers it says in Hashkiveinu:
והסר שטן מלפנינו ומאחרינו
Remove impediments (satan/evil inclination) behind us and in front of us
The Chofetz Chaim asks that in "in front of us" is obvious since he is blocking us from doing good deeds. What is "behind us"? He explains that sometimes the evil inclination can push us from behind to do more mitzvos. Why? To damage us, like giving too much charity so we become destitute. Or to stay awake learning Torah so we become weak the next day.
An excited "Baal Tshuvah" might be experiencing this Yetzer Hara. They should know what is "too much", but also don't do "too little". It is a hard balance.
The Rambam and many others explain that to find the "middle road" which is desirable (ie: to not be extreme) one (who is accustomed already to an extreme) sometimes must push themselves beyond the middle and relax into the middle road. For example a stingy person might need to spread too much money (beyond the normal charity) to accustom himself, and then to stop and relax into the middle road. (Chapter 4 of Introduction to Pirkei Avos).
So perhaps done with keen insight this can be a useful tool for character development but done with pure emotion and no thought, can cause burnout causing more destruction. For this reason I always suggest caution and to go slow when uncertain, but this is my personal nature.