Is is judicious to worship some one unknown as God

When I and my friend( from north india) was going through our campus .We found a temple of someone, whom both of us did not know before. But although he did not know the one who is being worshipped there , atleast the name of the goddess. he went to worship it.

Then I asked him how could you go and worship the one whom you dont know?
He answered ,whether i dont know who it is , i in my heart worshipping the real God indirectly by bowing to it , & God wud understand it...

Here is my doubt:;

I believe God is my father , who has the heart as a person do.
So for example if your son says thankyou or kisses your photo, or to some object or someone saying it to be a dad, even thou you are beside and eagerly waiting for your son to kiss you....How do you feel???:(.

It is what God feels if you bow before some one foreign with out really knowing who is the real God.....