A few more extreme examples.
I was never a metal fan. So when a friend of mine gave me Metallica's Justice album, I hated it. Took a few months of him constantly bugging me to listen to it before I finally started liking it (and metal in general).
In a similar vein, my sister really liked Ministry's synth pop phase. So she picked up The Mind is a Terrible Thing to Taste. Naturally, she hated it. She gave it to me. I hated it too. 3 years later, I'm actually into metal now (because of Metallica), and I really dig Ministry's new album, Psalm 69. So I re-buy Mind is a Terrible Thing to Taste and find it's a really good album.
A third example, the public library opened a "teen" area which has an immense CD collection. So I'm there every week, picking up almost anything that catches my eye. I see an album with an interesting cover and pick it up. It's the most tuneless piece of crap I've ever heard. The band was
Cryptopsy and the album was
None So Vile.
Years later, my taste in music has gotten more and more extreme, as I find music to be really extreme to be considered "hard." I find another copy of the album in another public library. I pick it up. Still hate it. The growled vocals that are completely unintelligible is something I can't stand. But it turns out that they fired their vocalist (Lord Worm), and replaced him with a more intelligible vocalist. Those albums aren't bad at all.