forgive i will, forget i won't

i am really really angry and why shouldn't i be? i am asking myself...
we had a small Diwali party in office... organised by some of us, we sent out a mail to all in the office: let's assemble at the pantry at 12 noon and have a small get-together...
we got the food, were all ready, waiting for our colleagues to join in... some who were out on assignments rushed back as soon as they were done...
some other people, however, were conspicious by their absence... they did not take calls when contacted and did not excuse their absence...
and they were home for lunch!!!... this while we went all the way to join in their Iftaars...
since some of us work on two shifts, our friends came back and headed for the pantry saying, "is there food for us?"
some of my colleagues do not know what to read into this initial absence followed by taking food when the party is over...
i am confident that they have deliberately not come: if the meet is at a particular time, they should have been there, or else have had the courtesy to inform us...
should we make an issue of this? or should we carry on, move away from this? the latter seems more of an educated choice... this is how we have been bred, nurtured, indoctrinated...
the seething anger will settle, we will have to carry on working... and though i will possibly forgive them when a new sun rises, i may not be able to forget this...