Oh boy... try raccoons squabbling through your camp in the pitch black.

There was an overnighter in Sequoia NP I did when something with heavy footsteps went by, then there were crashing noises that sounded like rocks being overturned, then something wood being torn into... the bear didn't bother my canister or me but it was sure having fun with downed trees. That was the trip I got up the next morning and discovered bear scratches on the tree next to the tree I tied my hammock to.

The most annoying and consistently bothersome noise was a guy in the tent near where I camped in a Yosemite backpacker's campground - he had somehow not brought a sleeping bag, and was using a space blanket. Every hour or so there was about ten minutes of rustling as he tried to get comfy. (We won't talk about the other noises he made. Darn Mountain House!)

No laughter here. Listening to a bear ripping up stuff is darn scary, as is listening to any footfall or rustle you haven't heard before. I talk to the critters - they go away. Heck, I was talking to the full moon one night, thinking it was a backpacker wandering up the ridge with a Maglite, it was so bright!

Don't be too startled about falling branches or pine cones if you are in forested areas. That freaked me out for a good while and started me looking up before I pitch camp. As long as you are under young green trees nothing too heavy will fall on your tarp/tent.