I used to hate カラオケ (karaoke). Before Japan I hated it because it involved singing in a bar with some douchebag DJ who decided whether or not to play the song you wanted to sing to. It also involved singing like a fool in front of the entire bar.
Japan's version of karaoke is light years better, as the technology is better, there's no douchebag DJ, and you only have to make a fool of yourself in front of your friends in a private room. But I still hated it. Why would I want to sing over some cheesy synthesized version of one of my favorite songs, when I can belt it out over the real one at home? To boot, the karaoke places almost never have what I really want to sing.
The discovery I made rather recently was that alcohol (so often as is the case) is the key. I went out with Pete and Will for a Boy's Night Karaoke session. We got drunk and howled to our hearts' content to such classics that you would never want to be caught dead singing in front of your friends.
Now I've realized that karaoke can indeed be very fun. Just add a smattering of know-how (don't choose songs you want to sing but rather songs you think will be fun to butcher), good friends,and more than a sprinkle of booze.