I made a warlock purely because of how awesome the sound effect of Summon Felsteed was. (This character eventually made it to 60 and did the Dreadsteed questline, that mount made it more awesome.) I am sad they changed the sound effect.
I made a shaman(Orc of course) because I loved the sound of tossing Windfury on my weapon followed by Lightning Shield.
Though I think some part was also due to stuff being new and exciting back in classic.
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