If I had watched the finale a few years ago, I would've been extremely disappointed. What about all those burning questions that I wanted answered, dammit?! In fact, I felt disappointed for most of this season--I still wanted those answers, and knew they weren't going to have time to give us all of them.
However, something about this finale just worked for me. It really (as lame as this is) made me realize that sometimes you don't need all the answers. Sometimes things just happen, and you don't get to know why. What you do get, is what you get. And whatever you can take from the things that leave you wondering in life helps you to grow and, hopefully, become a better person. If you think about it, the characters had no idea what was going on half the time, either. They were just as lost (haha) as we were on the sonic fences and numbers, etc. And they all grew throughout the three years they spent dealing with this island.
I have to say, I kind of like that a lot of things were left open-ended. I'm sure lots of people don't like the idea of primetime TV being all preachy or "teaching a lesson"; most of us would rather go for the instant gratification of having a show explicitly give the answers that we want. But I think that's what makes Lost so special, is that it's not just another TV show that does that. It's an experience. And if you want the answers, that's up to you to decide what it all means to you.
Such an amazing journey, and truly a work of art.