Lyric discussion by SFP 

Cover art for Gonna Leave You lyrics by Queens of the Stone Age

"Three years too long You know this is wrong "Everything" scars the skin Push it in, break it off"

He's talking about putting the needle in his arm. I think the three years too long is the length of his addiction. Everything scars the skin. Push the needle in. Push down the plunger.

"I'm gonna leave I'm gonna leave you"

I'm gonna quit the heroin.

"I gave it a start I stomped on your heart This the is the end, No more pictures, we ain't friends It's raining in my room There's blood in my spoon You're out of my highchair I'm out of your womb"

I think the I gave it a start refers to his starting the drug. He's totally quitting her. There's blood in his spoon from the boiling heroin in the spoon.

"I'm gonna leave I don't need you " I don't need you to live happily.