I'm convinced that every boy, in his heart, would rather steal second base than an automobile.

The line contrasts two kinds of “stealing”: the illicit thrill of taking property (an automobile) versus the sanctioned daring of stealing second base in baseball. Clark’s point is that many boys are drawn less to material acquisition than to risk, speed, and the chance to test themselves under rules that make the danger meaningful rather than criminal. The quote nostalgically elevates sport as a socially acceptable outlet for youthful competitiveness and rebellion, implying that the deepest desire is for excitement, recognition, and mastery—not for possessions. It also hints at baseball’s cultural role as a formative arena where character and ambition are expressed.