Yea, I agree with Thornir, there are many kinds of perfect days.
I think one of my happiest days was in Jamaica, on my honeymoon. The wife unit and I would hang out in the pool next to the beach, and swim up to the bar and get a pina colada. It doesn't get much better than that. Those were great times.
Gen Con is another kind of great day. Waking up, taking a quick shower, and then just soaking up gaming at the dealer hall, and gaming, and hanging out with friends all day, and then just crashing at night. That's great fun.
I've actually had great days at work, where I felt like I'd accomplished something, or written some great lines of code, or solved some hard problems, or made great progress on a project. Those days are good, but unfortunately very few and very far between.
The day my daughter was born was a great day. Or maybe the day we brought her home for the first time.
The day I proposed was pretty awesome.