Is there any word for a person who moves frequently between two extremes in everything
A good description is the idiom "She runs hot and cold," (which indicates extremes of mood and behavior.)
all-or-nothing [awl-er-nuhth-ing] adjective -dictionary.com
- not allowing for qualification or compromise; either fully or not at all operative: an all-or-nothing approach.
Having asked myself this question, I've found that the acronym AON hasn't really caught on yet...
I'm an aon: a real, all-or-nothing kinda guy. I will haz cake and eat it too, or I don't want any at all.