The quote above is not the most scholarly translation of that thought by Epicurus.
I’m not proud, I like the way it rolls off of your tongue and the meaning is fully intact.
It is a powerful quote.
I think it provides an insane amount of comfort.
I don’t think it provides complete comfort.
Marcus Aurelius suggested a rhetorical question ( for a context other than this post ), paraphrasing, “Am I afraid of death because I will not be able to do _____ anymore?”
I think that is the first reason people feel angst about death. They think about missed opportunities from the past and things they will not be able to do in the future.
I think another reason people feel angst about death is the handy dandy quote above. They haven’t worked that thought down into their bones. They will never experience being dead. If there is an afterlife, then all that worry is for nothing, so you are “good” on both counts.
I think there is also an animal, instinctual fear of death we inherit. I don’t think we can do much about that. If we can reduce that emotional reflex in regards to our own pending demise or the demise of someone close to us we are ahead of the game.
Possibly, there is a cognitive, cultural component on top of that animal instinct. Just beneath your level of your self awareness you think you should freak out when someone dies. Why? It will not do anything for the deceased. While they were alive, if they thought about such things, they decided they didn’t want their survivors to suffer over their death. They likely thought it would just be nice to be remembered once in a while. If there is an afterlife, and they weren’t republicans, they are probably having a grand old time. Feeling angst about your demise doesn’t help anyone either. You are still going to die. You are better off without the angst, enjoying the time you have. So again, why freak out? It isn’t doing anyone any good. In history, people used to move to different parts of the globe for life. No smart phones, no social media, no email, and not even a post office to deliver letters. That is what it boils down to when a person close to you dies (almost). They moved far away, such that you will never be able to communicate with them again. Memorials are a going away party that happened after the fact because something happened to their travel arrangements such that they had to leave on short notice.
Nobody wants to grow old. Seeing people close to you die or grow old reminds you of that. Growing old sucks, even the historical Buddha said that. Your physical and mental capacities diminish. On top of that there is a cognitive and cultural component on top of that. Many horrible things about old age and old people.
You can’t do much about that animal instinct. You may be able to do something about your culture conditioning, though not completely. You can work at aging gracefully, not just physically, but with your beliefs. There is a bit of luck in how well that will turn out, things beyond your control. At least you can tell yourself you tried. In regards to your FOMO ( Fear Of Missing/having Missed Out ), you are still alive, so you still have a chance at doing some things of value to yourself.