Don't trust people

• Penny: He's a really good looking guy and I thought he was kind of cheesy at first.
• Dr. Horrible: [under his breath] Trust your instincts.
• Penny: But, he turned out to be totally sweet. Sometimes people are layered like that. There's something totally different underneath than what's on the surface.
• Dr. Horrible: And sometimes there's a third, even deeper level, and that one is the same as the top surface one. Like with pie.