The purpose of the creation of man and jinn is as the verse states:
“I have created the jinn and men only so that they may serve Me (by means of manifesting the qualities of My Names).”
As can be seen, it is to worship Allah!
This act of worshipping is fulfilled by humans and jinn at all times; they are constantly engaged in the act of worshipping Allah. The verse doesn’t say “they may worship me if they like…” It is an absolute statement. The fact that they are created for this purpose means they are all fulfilling this whether they like it or not, without exception.
So, then the first meaning to take from this is humans and jinn are constantly in a state of worship to Allah, which is natural worship. Here are two verses that further clarify this:
"The seven heavens (all creation pertaining to the seven states of consciousness), the earth (the body) and everything within them exalts Him (tasbih; fulfill their functions by constantly manifesting in different ways to express His Names)! There is nothing that does not exalt (tasbih) Him with hamd (evaluation of the corporeal worlds created with His Names, as He wills)!" 
Say, “Everyone acts according to his own creation program (natural disposition; fitrah)”
Acting according to one’s creational program, i.e. manifesting the meanings of the names that comprise their existence, is their very worship!
This is how they fulfill the purpose of their creation.
The second meaning to take from this is that a group of humans and jinn will know Allah. One of the learned followers of the Rasul (saw) construes the word “serve” as “know” i.e. to know Allah!
Surely this points to a small minority amongst humans. And if we take this as the only meaning then the prior meaning, that man and jinn is created to worship Allah, is rendered invalid.
But the verse, “Everyone acts according to his own creation program (natural disposition; fitrah)” makes it evident that everyone acts according to the meanings of the names that comprise their existence. Hence, your actions reflect the meanings that compose you! So whatever name you are given, that name, say Ahmed, is a name that is given to the particular form of expression of the names manifesting from that composition. There is no separate existence from the meanings, i.e. the names aren’t separate from the meanings they reference.
Since there is no other existence, whether we call these meanings Ahmed or Cemile, every act that is expressed under these names, are simply the expressions of the meanings that comprise their being.
This being the case, the temperament of that person, their natural disposition, or what we call their emotions, are just the manifestations of the names that make them up. In other words, it is the natural output of the meanings of the names that compose their existence.
Hence, anyone who lives with this natural output is necessarily fulfilling their natural worship!
But alas, the result of this natural worship in the future, is hell.