You know, I really didn't even think much about my own answer when I asked the question. As stupid as it sounds, the day of marriage to my much beloved husband of almost 30 years really does qualify as one of the best days, but not because it was our marriage. It was because I could give my parents a weekend in Hawaii (we were stationed there) and because my paternal grandfather died then. It was an important family moment, but saying it was one of the best days in my life wouldn't be right.
One of the best days of my life was one day, and this will be silly, that my best girlfriend in the world and I were going home after Thanksgiving at my house. Now, for many of you, that isn't that big of a deal. But we were overseas, her father was an officer, mine an enlisted man. It took a lot to get this together. The fog was incredibly thick. We didn't live that far apart, she and I would walk it regularly. But I remember sitting in the back of their car (our parents had told us if we cleaned up after the meal, I could go spend the night with Colleen, and believe me, Claire and Colleen cleaned like you wouldn't believe). Anyway, I remember thinking that I wanted to remember that moment for the rest of my life. Everything was just perfect, and I was 12 years old. To this day I do that. Sit there for one moment and tell myself, life is perfect right now. Remember this. Marriages, etc, grand moments like that are too stressful to be perfect moments. They may be, historically, great milestones in your life. And in some cases they are the best. Simple moments.