"I accidentally sold the Heart of Darkness to a peddler 3 towns back, sorry. In my defense, it was right next to the wolf pelts in my backpack"

Yes but what I hate even morr is when a quest item remains in your inventory after quest completes and I have no idea if I will still need it or if I can throw it away.

I'm paranoid about this. When a game has a "junk" tab in the inventory with an option at stores to "sell all junk," I know there's going to be a quest to give a generic silver ring or a jade statuette to someone.