My definition of "forgiveness" has changed quite often. Lately, to me, it means accepting that things couldn't have been any different, that things happened according to a non-judgmental, benign fate. That being said, I'm also venturing to think that maybe it is possible to forgive someone, and be angry at him/her at the same time. Anger is a natural reaction to injustice; I think it should be inevitable it (re-)surfaces from time to time. I guess my stance now is more moderate - that even with forgiveness, there is space for anger (which hopefully can be translated into motivation to change things) and sadness, while at the same time allowing me to let go of more unhealthy, potent feelings like rage and hatred that I would otherwise feel...
My 2 cents, for what it's worth.