Billy and his cohort Fred were once bullies, picking on Carlos and Rad—though as Fred was largely unmotivated in this area, Billy served as the driving force in their antagonism. He also briefly plotted to win Alexis over romantically, but Billy's plans for this and any other short-term goals were ultimately unrealized due to the coming of the Transformers.

Billy and Fred eventually became friends with their one-time targets, in particular spending a lot of time around Carlos.

(Source: Transformers Wiki)