Even though Hinton characterizes Bob as a big, cruel, and popular Soc at first in The Outsiders, the reader discovers that he actually shares several similiarities to vulnerable Johnny Cade, the small Soc boy that he so viciously beat up.
Both Johnny and Bob felt that their parents had failed them. Johnny and Bob's parents were at extreme ends of the parenting spectrum; while Johnny's dad is abusive and his mom, neglectful, whereas Bob's parents spoiled him rotten. Randy confessed to Ponyboy that Bob pushed the limits with his parents so they might "say 'No' and they never did" (116). Randy felt that if Bob's parents might have been firmer with their son, then he might still be alive.
On the other hand, Johnny's parents made his life miserable, and despite all of that, he still asks Dally if they were worried about him after he ran away. When Dally replies in the negative, Johnny "stared at the dashboard with such hurt bewilderment that [Ponyboy] could have bawled" (88).
They both have some parents issues.
They both reach premature death, Bob was stabbed by Johnny, and Johnny was crushed in a church fire.