Following is what I wrote in the old thread about discovering Mahler:
"I cannot say that, upon hearing a Mahler work for the first time, I was immediately hooked on Mahler. For me, Mahler was an acquired taste, and it took some time for me to get accustomed to his music.
I first heard Mahler in the mid 70's when I bought Bruno Walter's Columbia Odyssey recording of the 9th. I read the liner notes, and found Mahler's story touching, and the music poignant. However, I did not pursue any of the other symphonies.
In college a year later, one of my roommates was heavily into Mahler, and had most of the Haitink recordings. I could not get interested in them. I found the "Brüder Martin" march in Symphony No.1 to be ridiculous (though I liked the first movement). I found it odd that there was singing in so many of the symphonies, and some of the symphonies seemed too long. I was particularly bothered by the fact that the first movement of No. 3 had to be split to two LP sides! However, I later heard the early Columbia Bernstein recording of the 3rd on the radio one day during a long drive, and I found the symphony fascinating. So, gradually, I began to acquire a taste for the rest of Mahler. His polyphony had always sounded like cacophony to me, but eventually my ear began to appreciate all those sounds playing at the same time.
Eventually, I had another roommate who was also into classical music, who hated Mahler. His objections were much like mine had been. Eventually, something clicked for him as well, and another Mahler proselyte was born.
Just remember that when you play a Mahler symphony for some people, they may react negatively, but will hopefully warm to his music over time. When my wife and I were married almost 20 years ago, she had never heard much Mahler, but over time has become quite a fan. There are still a couple of symphonies she does not know terribly well, but now that her ear "gets" Mahler, she is usually open to all his music."
I would add that I responded positively to the 9th right away, because it seemed more "normal" as a symphony to me. The others seemed strange (more than 4 movements, singing, excessive length, etc), and took some time before they clicked with me. I eventually came to love all the symphonies with the exception of the 8th.