Dad Jokes Galore
If you want to hear the dumbest joke about a man feeding brandy-laced milk to his mother, look no further than Buck Barrow. (Especially if you want to hear it multiple times.)
Buck Barrow is the cheesiest man in the world. He tells dad jokes, and has a smokin' dad bod to match. He routinely yells out "Woo-hoo!" and throws fake punches. He calls Bonnie "sis" as soon as he meets her, and asks her if she's taking care of his baby brother, Clyde.
In short, he's the perfect guy to have around if you want to diffuse a tense situation.
The gang needs him for just this reason. Bonnie's too moody. Clyde's too manic. C.W. is too slow on the uptake. And Blanche is—well, Blanche is kind of useless.
But Buck's the life of the party, and he's the perfect right-hand man for the B & C team. He's no stranger to a life outside the law: he's done time in prison and knows how to fire a gun. When he kills a police officer, he knows that he's in it to win it (or, most likely, to lose it).
Some of the movie's most uplifting and funny moments come straight from Buck. When the Barrow Gang kidnaps Eugene and Velma, Buck keeps the mood jolly:
BUCK: What's your names?
EUGENE: I'm Eugene Grizzard.
VELMA: I'm Velma Davis.
BUCK: Well, we're the Barrow Gang. That there's Clyde driving. I'm Buck. That's my wife, Blanche. Bonnie Parker. C.W.
[BUCK cocks his gun.]
BUCK: [to EUGENE] Now, boy. When you going to marry the girl? [BUCK starts laughing uproariously.]
Buck's like a very hospitable frat boy: he'll introduce you to everyone, pretend to threaten you with a gun, start laughing, and then buy you a burger. Even when the rest of the Barrow Gang is looking bored with the fact that Eugene and Velma are along for the ride, Eugene is yukking it up with his lame jokes.
Although there are plenty of grim moments throughout the movie, it's when Buck dies that we know the end is truly nigh. Buck's death (and Blanche's capture) signals the end of the liveliness of the Barrow Gang, and therefore the end of its life.
Without Buck around to be his dopey, carefree self, the reality of outlaw life sets in. In his absence, Bonnie and Clyde realize the extremity of their own situation… and they can't even think up a corny joke to take the edge off.