I totally agree with MurderMachineX and CrazyTrain0917. I prefer playing with my mic off because it helps me concentrate on the game. Some of my highest round records in the first BO zombies were actually with randoms who did not have their mic on. I usually mute someone if they're blasting music so loud that I can't hear if a zombie is behind me.
As for funny things I hear people say:
People freaking out at my points (How the f*** does he have 20k points? It's only round 2!)
People calling the denizens "zombie babies" or "flying zombie babies"
People asking where they can PaP
People cursing at a zombie for destroying their turbine (trying to open PaP)
People's reactions to seeing the galvaknuckles for the first time
People's reactions after finding out you can store a weapon in the farm and store points in the bank vault
People going off somewhere else in the map, going down, and yelling "come get me" on the mic
People asking what the turbine is for (also people trying to use the turbine on a buyable door )
I was in this pub match where everyone died at the diner while I was running in the fog. I tried but I couldn't get to them in time. Anyways, I took the last zombie to the bank, punched the drawer, created a drop worth a few thousand points (I think it was around 5k), and killed the last zombie. I watched as they all sprinted for it the moment they spawned. For some reason I found it amusing. Thinking back now, I wish I recorded it.