It's funny how different people are. If I'd been this kid and someone was snarling "Ordering a pizza?" at me, without even thinking, I would have snarled back "Yeah. You want pepperoni?"-Maximum Ride
"It's funny how different people are," highlights the idea that individuals react uniquely to situations. The quote reflects on the contrasting reactions people might have in similar circumstances, emphasizing personal differences in behavior and personality.
In this case, the speaker considers how they would respond if someone was teasing them about ordering a pizza. Instead of showing offense or annoyance, they imagine confidently joking back with a playful remark about their pizza choice, illustrating their personality as bold and humorous.