What makes you a Singaporean?

Am I one because I hold a Singapore passport?
Or is it I have a pink IC?
Because I have to serve NS?
Or is it because I live in a territory that is politically divided as Singapore?
Maybe its the local food here?
Could it be because of the people I know that makes me feel at home?
Perhaps it's the HDB & the ownership of home?
The education teaches me that I'm Singaporean?
It can't be on my physical features then?
My almost perfect Singlish?
The local culture?

I can't find an answer to this. I need some definition that can tell me what indeed constitutes being a Singaporean. arghhh... Identity is such a difficult concept, I cannot seem to catch hold of it no matter how hard I try.