In the Garden of Eden, where the first man Adam lived, there was no disease, no suffering and no death. So, were the people there happy then? No they weren't. They experienced nothing in relativity, and they couldn't feel happiness because as they never went through unhappiness. Only those who have experienced sorrow, poverty, diseases, and suffering on this earth can feel true happiness and give thanks to God from their heart when they enter the heavenly kingdom where there is no suffering.
"'For I know the plans that I have for you,' declares the LORD, 'plans for welfare and not for calamity to give you a future and a hope'" (Jeremiah 29:11).