I was thinking of making a similar thread on songs you didn't get so much when you were young, but make more sense with age.
As Swiss said, there are entire bands and styles I didn't dig so much that I listen to now.
A few points:
Rush: Time Stand Still. I though the song was alright when it first came out, but never really got it. But when I saw Rush a few weeks ago, and they played it for the first time in years and years, it just suddenly made more sense. I think because now I'm closer to the age the band was when they wrote it. Having a family and kids now, I can relate to the song far more than I did as a kid.
Another one is the entire Raised on Radio album from Journey. It came out when I like 15 or 16, but at the time, I was mad they fired Steve Smith and Ross Valery, so I didn't buy it right away. I eventually did get a few years later, just to complete my collection. And I just didn't really get where it was going. But now that I'm older, and I've been through many of the life experiences that are covered on that album, I say I get it now. I see what they were trying to do. I still think Smith and Ross should have been on it though. But all those songs make so much more sense, and are so much more enjoyable now.
Other things:
When I was younger, I had this rule that I won't listen to any band that uses drum machines. I was very against that. But then one day, I just had to make an exception. Then another. And 10 +years go by, and I suddenly realize, you know, it's dumb rule. A good song is a good song. And thus, through my wife, I've grown to appreciate things like Depeche Mode, Sisters of Mercy, and other stuff from the 80's I wouldn't have been caught dead listening to at the time.
Fleetwood Mac is another. Their hey day was the 70's, but it wasn't until 10 years ago I started to get what they were about. Obviously, I heard them on the radio 10,000 times, but I never got it.. The Chain, Gold Dust Woman, and such were awesome songs. I can't believe I never paid any attention to them before.