I've been critical of Kübler-Ross's grief stages mostly because it's been detrimental to my recovery from the loss of my parents. I didn't really pay much attention to the stages personally, but those around me expected me to follow this strict guide of when and how to feel. I know this is a gross misapplication of the grief model, but the misapplication is societal. In both deaths, when I wasn't following the prescripted stages I was questioned and bullied over it. What this ended up causing was for me to retreat further within, thinking I was experiencing death the wrong way. Eventually I just shut it out entirely and it festered like an infected wound for years while I consciously tried to bury it deeper. My whole issue comes from the way grief models are presented. They're usually listed, and even with warnings ("please don't use this as a list!"), we still do. Perhaps if the model was some sort of visual graphic it could better represent the seemingly universal moods that we can all connect with. I don't doubt there isn't a fair set of emotions we all may feel, but we all experience bereavement so radically differently I fear even suggesting, say "anger" (one I haven't personally encountered) as an emotion present in grief will present a problem for people who haven't felt it.
Lauren J. Breen and Moira O’Connor note the fundamental structure of grief through psychology analysis also fails to consider grief doesn’t always align to specific functions. They posit that this creates a paradox for complicated grief: a cyclic interference in what may actually be healthy grieving following a delineated path. By medicalising grief, and assigning a diagnostic category, we create a self-fulfilling prophesy of damaged individuals. This does not, in fact, prove that complicated grief isn’t a thing, rather, it proves its existence by default. Until a society can understand death, we will not have the correct capacity to deal with it.
 Breen, L. J. & O’Connor, M. (2007) “The fundamental paradox in the grief literature: a critical reflection.” Omega: journal of death and dying. 55 (3) 199-218.