Wow mackro, I'm like 180 degrees from how you feel.
I love LPC, but I've always found Volume 1 almost unlistenable. I guess it's because of the mix of the uber-low fidelity recordings, and just that he was so young and barely not laughing during a lot of the calls. You can tell he's just some punk trying to mess with his teachers and authority figures, and those kinds of calls never appealed much to me. Also, the weird sound effects between calls remind me of "Life Remote Control" in Exit Through the Gift Shop.

Volume 2 is almost 100% him calling the meat packing place, which gets tired pretty quick, too.
I don't feel like he became comfortable and found his voice until the third album. That's when he first started messing around with long-form calls (like the vitamin salesman telemarketer who calls him -- HOLY CRAP), celebrities, three way mashups, and weird effects. That's when things started getting really surreal and interesting to me.
Volumes 3-5 + Late Eighties Vein are all classics to me, and most of the tracks from them are burned into my brains.