Some students take offense very easily.
During one lecture, a student asked a question I’ve heard many times: “If we evolved from monkeys, why are there still monkeys?” My response was and is always the same: we didn’t evolve from monkeys. Humans and monkeys evolved from a common ancestor. One ancestral population evolved in one direction toward modern-day monkeys, while another evolved toward humans. The explanation clicked for most students, but not all, so I tried another. I asked the students to consider this: Catholics are the oldest Christian denomination, and so if Protestants evolved from Catholics, why are there still Catholics? Some students laughed, some found it a clarifying example, and others were clearly offended.
Two days later, a student walked down to the lectern after class and informed me that I was wrong about Catholics. He said Baptists were the first Christians and that this is clearly explained in the Bible. His mother told him so. I asked where this was explained in the Bible. He glared at me and said, “John the Baptist, duh!” and then walked away.