well: those who I have heard say they'll be dead soon, often died within few months ( terminal cancer, fatal accidents,...). This is why I asked.
Now effectively, time is limited in this life phase , and we have one certitude: one day, each person will die. Then after - from religious people who have assisted to people's deaths, and then atheists scientists who turn religious from their job experiences of talking to those who are dying- we will have a face to face regarding our "Book of Life".
Now about happiness and joy. Most define happiness, from what they learn from the media: aka material and physical gratifications, thus the research for more physically stimulating experiences to cover the "emotional toxins" in the person, with extremes like exagerated indulgence. I have noticed that many people after some serious mediations retreats are happier or have more joy: it seems like they have removed a lot of "emotional toxins".