GRIEF is about loss. It is a deeper emotion associated with the absence of what you want (or love) hence the sorrow and sadness. When you cannot see a future without what/who has been lost this leads to inconsolability (i.e. feeling devastated or not easily comforted or able to ‘see the light at the end of the tunnel’).
JOY is what permits you to see the light in the horizon. Even though it can be difficult to experience JOY when in such intense pain, you can start to feel better by having fun. That is, living in the moment by doing enjoyable things (e.g. drinking a good cup of coffee, eating your favorite meal, watching your favorite movie or taking part in a hobby). These activities will allow you to get in touch with who you really are which creates happiness. This will lead to enthusiasm about life once again thus assisting you to go about getting what you now want (which may be very different from before the loss) or by allowing the new to come in replacing what has been lost (e.g. a new relationship, sense of purpose, job etc.).
An excerpt from “DIY Therapy Chart: an Emotional Healing Guide”.