Magic Forums

I read on the interactive FAQ that it's impossible for any human,regardless of how talented or trained one might be,to transform into an animal,to change his/her physical appearence or to become a God/Goddess,Demon/Demoness etc.
If so,then why does the Immortality spells and Fantasy Spells categories even exist? Are such spells simply fake (I know some of them should be) or what I read about magick's limitations is too strict?
Also,I'd like to know what magick can really do and cannot do.I was very dissapointed when I read that it does not matter how much I struggle,nor I nor anyone else will ever be capable of doing this and that,that neither...It's really killing me because it's simply not fair! I thought magick is not just like science,with strict limitations and unbreakable rules...