I'm a packrat (even in real life), and a compulsive looter-hoarder in games that have lootable bodies/containers. I loot every body I find, open or crush every container; hey, you'll never know when something can be useful!
In games like Skyrim & Fallout 4 that have character weight limits, I'm often find myself slowly trudging back to either one of my home bases, or to the nearest town. I love the tense feeling I get being over-incombered (even w/ Lydia to carry my burdens) and trying to get to a safe location before a dragon attacks, or a deathclaw in FO4. I don't even know the number of times I've died, or nearly died, trying to fight with my mobility severely restricted by carrying too much. I know there's mods that alleviate that, but I like the risk/reward aspect and the danger. My choice, my risk.
It's not just good loot either. In games with crafting systems, or house/settlement building, even the most mundane things can be broken down into parts that can be used for those systems. Specifically Fallout 4, where I'm constantly searching for adhesive, circuitry, glass, and a variety of other components; I pick up absolutely everything laying around: every gun, glass bottle, newspaper, ect.
Then there are games that don't have weight limits, but size limits to your carry inventory. Those represent a different set of problems, and I will, very reluctantly, leave some items on the ground. If there's a fast travel option, like the Town Portal Scrolls in D2 Resurrected, I'll often go through several of those just to collect all the loot in an area.
So, yeah, I am, I admit it. If there's a looters-hoarders-packrat anonymous number, I should probably call it.