I'm atill checking every container because apparently this game is just packed with missile stuff and I don't know when I'll find something important. Plus I still find myself needing to scrounge for stuff to sell for money for supplies, so I generally can't afford not to search everything I also can't shake the worry that maybe something worthwhile will be in something, even if it's not valuables then maybe a book or an item that will turn out to be useful for some random puzzle somewhere in the area and it sucks and is tedious and I don't know how you manage not doing it.
Ah … I was once like you, my child, but then I learned to let go of material things and took one step closer to nirvana

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Seriously though, I personally find the game more fun when not looting thoroughly. Partly because clicking on everything is boring but also as it makes resource management more interesting as I don’t end up with quite such an excessive amount of money, potions, arrows, scrolls or food. Not that they’re scarce even so, but it felt impactful when my party had to change its pace and start being more thorough in their looting and pick up even lower value items to sell because they were starting to run low on healing potions or when my paladin accidentally broke their oath and didn’t have 2,000GP to reinstate it (the oathbreaking itself was still annoying but at least restoring it felt a bit more meaningful!). There’s also more variability between different playthroughs depending on what and how much I loot - my curious gnome rogue ended up with tons more stuff than my paladin whose mind was on higher ideals of justice.
I personally would prefer Larian didn’t just make it impossible to interact with uninteresting stuff as I’d find this less immersive, there’d be less opportunity for the sort of change in pace and approach I mentioned above, I wouldn’t want to deny folk who do seem to enjoy looting everything their fun, it would restrict options to find other stuff to do with random containers and so on, and I’m not
entirely joking when I say that I also wouldn’t want other players to be denied the epiphany I had

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But I would be all for some additional 5e-friendly ways to identify magical or unique stuff, such as the Detect Magic spell or the ability to actively roll perception to find unique puzzles, quest items, etc, and/or have this highlighted as the result of passive perception rolls. I’d also like the behaviour of the alt key to highlight stuff to be more consistent, or at least I don’t understand how it decides what does and doesn’t get highlighted at the moment. It might be nice to somehow tie this to your party’s perception, too, but perhaps that’s overcomplicating things.