Cowboy Hat Mania
Start at the beginning of Act 1 Chapter 3 "Rolling Thunder" on Insane difficulty. There are 3 cowboy hats in the area and you will need to take out your pistol and shoot them. Skip the dialog and continue.
Make sure you are facing the direction the rig will be moving, the first is on the side of the building behind and to the right of the rig.
The second is between the front wheel and back wheel of a tank sitting to the left of the rig.
The third is behind the second large gas tank next to the tank with the previous cowboy hat.
Shooting all 3 will give you the following effects:
All characters on the rig will immediately equip cowboy hats.
In the next chapter, if you fail kill the driver of the hijacked rig in time, when you see the cutscene of your rig falling into the ravine, you will see a cowboy hat floating down to earth.
If you succeed to kill the driver of the hijacked rig, he will be wearing a cowboy hat when he hangs out the window before the cutscene.
During the cutscene where the hijacked rig falls into the ravine, you will see a cowboy hat falling down to earth.
A corpser that emerges from the ground later in the chapter will be wearing a cowboy hat and scream "YEE HAW!"
Meatflag with gamercard
After playing a game of submission if you press "Y" to check your game stats you can scroll down to the meatflag and you will see that they also have a gamercard with a profile written in detail! Not only that, the meatflag even has a few achievements.
Who wants toast?
In act 4 chapter 5, after rejoining with Dom or Marcus make your way down the hallway where locust ammo boxes are. There is a pedestal in the center along the wall. Shoot it with a weapon, shotgun works best but choose whatever you want and press "X". Hope you like crispy toast! Dom does...