It is in the way it is used.
   It's SO embedded in our language, we don't even notice that we
   do it.

   What is an affect? Can I point to it? Yes I can. It is a word in
   a dictionary. It is a noun in a sentence. A noun is replaceable
   by another noun.

   Changing "Affected by" - a verb form - into a noun called
   Affect, allows us some flexibility in how we use it in a
   sentence, but in the process, personifies it. We have turned an
   action into a solid thing, a noun, giving it properties it might
   not actually possess, because it is not a thing that can possess
   things, but rather moving/doing/being.