In the case of Freud one might of course argue about the cigar example since there were some strongly sexual issues in his life.

Subconscious is always present in everything people do, they're just not always aware of it (yeah, pun intended). Then again, it takes time for the subconscious to evolve on a level where it can alter the fears and desires and show them in a masked form in dreams. Also, a person must have some experience about the world for the mind to have objects to use for the masking (you can not dream about something your mind is not aware of). This is why - as Freud noted, too - this is only true in the case of people old enough. A young child does not have experience about the world, nor has his/her mind evolved enough for complex, abstract thought processes and, because of that if a young child speaks about strawberries in his/her sleep, (s)he would most likely want strawberries, without there being any deeper meaning in the dream.