In his 2000 book Angry Blonde Eminem explained how the song came to be:

The “Lounge” skit that goes before “My Fault” actually inspired the mushroom song: Jeff from FBT and I were in the studio and we had just knocked out a song, but we were trying to come up with more shit. Jeff was just sitting there, fuckin' around, singing a song that went something like “I never meant to…” Now, he never said, “give you mushrooms.” I finished it off and we both just started singin' it. We were laughin' and jokin' around and shit, until he went into this faster, more up-tempo rendition. He started singing, “I never meant to give you mushrooms, girl, I never…” And I just finished the hook off. It was really late at night, so we just came back and knocked it out the next day. We made the track first and then I took it home and wrote to it.
“My Fault” is actually sort of a story about one of my friends who had a bad acid trip. But it was a dude, though. He was having a bad trip and was talkin' about how he was worthless, how he didn’t have a job, and how he was just fucked up. He was going through a depressed stage and was even crying. I told him, “Yo, it’s okay.” So I thought, “What if I wrote it about a girl who’s fucked up having a bad mushroom trip?” It was actually going to be a single. I had done a clean version of it and put it on the Celebrity Death Match soundtrack. Interscope didn’t want to release it as a single, though, ‘cause if I came with that after “My Name Is” instead of “Guilty Conscience”, I would’ve looked like a fuckin’ bubblegum artist. Two goofy songs right back-to-back. That probably would’ve fucked me up till this day. The song… not the ‘shrooms.

• Russian Translation