I went to the Big Four at the Indio Polo Grounds, paid for the $200 tickets and everything.
I LOVE Megadeth. enjoy Metallica and Anthrax, and for Slayer... I loved South of Heaven, and then the rest... were okay enough. Just not my focus.
I enjoy SOME of most music, but a gonna buy every Megadeth album 'cause... I just am. Just like I bought every Stone Temple Pilots album because I went to the same college as Scott Wyland, worked in the same city where they started playing, and loved their sound.
I defs don't hate Slayer, but a lot of their music isn't for me, but you know what? Much like every game here isn't for me, I know it's okay if I don't love everything by Slayer.
On the other hand, from living in Okinawa in 1991 and Osaka in 2000 to August 2001, I do enjoy quite a lot of Japanese thrash type metal (X Japan, Tokyo Yankees, select Kuroyume albums, SEX Machineguns, Gargoyle, The Slut Banks, ZI: Kill, some Dir En Grey, select Fanatic Crisis, and maybe even some hide and Zilch).
So, you know, find what you like. Be tripped the fudge out by things that are almost certainly coincidence but throw you for a loop. Enjoy what you can, and move on happily without being dick about stuff for which you don't care.