I am often asked why I say "I love your guts" or where that phrase comes from. It's hard for me to remember exactly because it is something my family has always said, but I believe it started out as "I love your filthy, stikin' guts" said in my dad's best John Wayne voice.
I remember as a kid when someone said "I hate your guts" you knew they really meant it! They don't just hate what you did, they hate the person you are and everything you stand for! When I say I love your guts, it means the opposite. I see who you are on the inside and I love it.
It's as simple as that in my adult brain, I love your soul. So you know when I say I love your guts, I really mean it.