This is such an important and powerful topic, I have always loved how so many change the basic structure of the stages and especially how some refuse to think acceptance plays any role at all. However since all the powerfully happy people have always emphasized the reality of the universe being fine just like it is, I feel it is the final outcome of all our experiences and think acceptance fits well.
Why not consider what the denial then anger then guilt then grief then acceptance are implying in a sense of regaining healthy interaction and freedom from having the injury affect us.
When we are hurt and dont have a healthy way to catagorise it in our life, we first deny it, so by denying it we relegate it to nonexistence and have no need to deal with it. However since the hurt is real we soon see that denying it, is unreal, so we react to the fact of still not knowing how to deal with it, by assuming a selfcentered position of importance, focusing our attention outward by being angery at the situation or person ect. Since anger isnt completly effective, in our need for catagorisation to regain peace, we soon find our self important anger become self involved guilt, which is more true to our own role of responsibility in any hurt we experience, not as a cause, but for the hurt response we find ourself buying into. Being rather than outward driven blame, it is a manifestaion of our own responsibility for our own pain, but since it is still self centered, it will not allow us to really see the whole expereince and so as it becomes evident that guilt, tho helpful and more of a complete view of things than anger or denial,it is still perpetuating the inability to move freely amongst experience.
Because of that still self orientedness being ineffective in dealing with the original experience, and because we have exhausted the outward driven escape and found ourselves in guilt, the last resort of mental blame, in dropping pretense, we find saddness ariseing, where we surrender to a physical sense of emotion, not a mental/discursive construct of denial, other oriented blame or self oriented guilt, but a more basic level of experience, and as this saddness is allowed, w out considering, but just feeling a reality that is painfull, the experience that had been so consuming, to the degree of our surrendering any self or other than self orientation, we find what is now seen, felt, and known, to be an experience of acceptance, where the catagorization may be oriented in a completly different way. That is allowing the memory to exist but not to control ones living experience.
What I have noticed in this process, is that when we are experiencing any one of these emotional qualities, at whatever stage, we are really at odds and unresolved with the previous one. If I am angery, its really a denial thing, if we are feeling guilty, its the anger that is driving that emotion and so on. So that attempting to emphasize or work with the apparant and manifesting emotion, or to push ourselves into what we mentally consider to be the next or more refined emotional stage or space, we instead are ignoring aspects of the stage or reality we are actually still caught in, and continuing in a discursive, mental ego driven way rather than a natural, physical, emotional, stageular way.