I think the song is about a breakup...he looks back on the breakup and what the other person said and did, and realizes that they are now just strangers again. And bitter strangers. They no longer know eachother.
Strangers don't care for eachother....so he feels like he could just 'spit on a stranger' and it wouldn't even matter to him.
So two people that were once close are now nothing to eachother.
There is alot of sarcasm in the glee with which he sings that chorus.
I have a different interpretation...
I think the song is about a breakup...he looks back on the breakup and what the other person said and did, and realizes that they are now just strangers again. And bitter strangers. They no longer know eachother.
Strangers don't care for eachother....so he feels like he could just 'spit on a stranger' and it wouldn't even matter to him.
So two people that were once close are now nothing to eachother. There is alot of sarcasm in the glee with which he sings that chorus.