HL2 had a few. One I remember was when navigating a large pool of acid with zombies trying to rip off your gonads. (this might have been episode 2). At one point you climb into higher ground, which is partly fenced off. At a gap in the fence overlooking the pool of acid and zombies is a crate full of the SMG grenades and a stool, with a few beers I think. I know it had very little to no value at all, but you can just see from that example that you could paint your own story. A man might have sat there one time enjoying a nice cold beer and blasting zombie brains. Very small touch, easily skipped in 2 seconds if wanted. I enjoy it all the same.