I had a few good ones involving the exploding red barrels.
I like jumping and dropping them into the back of a pickup truck and then driving it into some enemies and shooting it.
Well, one time I tried it and I jumped too high over the truck (with maximum strength) and when I dropped the barrel it fell way too hard and hit the truck... the whole truck bed sank and the barrel sparked and exploded (while I was still in the air). Needless to say, I died...
Another time, I had just plopped a barrel into the back of a truck and was about to get in, then some Koreans spotted me and started firing. The genius that I am, I decided to run behind the truck for cover. I looked over the bed to see where I was being shot from, and then I realized the big red thing obstructing my view was the BARREL I just put there. I saw some tracers flying my way. BOOM.
That was the fastest they had ever killed me in that demo. Took about 3 seconds after they spotted me.
Another great one was when I was attacking the command post. I was hiding behind the big trailer (with the computer inside) and there was one guy hiding behind some sandbags on the other side, as well as a guy firing away with the machinegun on the edge of the cliff. I turned on maximum strength, grabbed a non-exploding barrel, peaked around the corner and tossed it.
I heard some screaming, the MG fire stopped... I looked and saw that BOTH guys were dead. I blindly threw a non exploding barrel and killed two men with it, one was about 20 feet away, the other was about 50.
Objects definitely do far too much damage to people. A rolling barrel will kill faster than 10 rifle rounds.