I believe it all depends on what the loss is when it comes to determining the various stages of grief. If someone close to you has died it's extremely difficult to be in denial if there's a corpse.
On the other hand if your mate dumped you or your spouse filed for a divorce and you were madly in love with them then I could see one going through denial, anger, bargaining, and depression before finally reaching acceptance that it's over for good.
Some people feel the same way about losing their job.
My goal is always to strive to reach (acceptance) as soon as possible. You can't move on until you get there. Once you accept something that is when in earnest you start making plans for recovery and figuring out what you want. It's important to keep things that happen in our life in perspective.
Today is just one page in one chapter within the book of your life. Always have the courage to turn to the next page.