When we discuss about it because I have chosen brunette Fawn, natural attitude pretty tough.Now I would like to see all the cartoons based on detailed study of the fairy's and think back of the decision based on appearance.
1. The franchise sucks
2. The so called "fairies" are not malicious enough to be considered fairies.
Seriously, fairies (And pixies, nixies, sprites, and damn near any kind of fey/fae) are little more than amoral tricksters that'll just as likely dump a bucket of water on your head as push you down a cliff for the fun of it.