A Child with over active hormones, and yet grows too slow, zits often times cover "a mitch's" face, and often have small teeth
"wow look at thatlittle kid, he sounds as if he smokes twenty packs a day, and just look at his face, there is barely a querter of an inch not covered with zits"
A 'Mitch' is a variety of human being, that is both extremist, and non-accepting of other people's beliefs.
The standard Mitch is generally Christian to the extreme, and unable to take in another person's beliefs. If someone was being a Mitch, he or she would be behaving in a way that shows he or she knows nothing about any other belief other than their own, and that it gives them the right to defend it at all costs. If someone were 'pulling a Mitch', they would be behaving in a way that shows they are extremely closed-minded, while continually telling themself that they're actually incredibly open-minded, when it is simply not the case.
Extremist, and one-sided.