Love makes time pass but time makes love pass

everything has an expiration date

I copy this from somebody and I hope she doesn't mind, well, she shouldn't because we are friend! Personally I found this graph quite interesting, in fact I just love graphs! Indeed it might be useful because it can be used as a reference to see how different it is to some outcomes. Of course this is just a generalisation of the vast majority. Question: What is the unit of love??