What does your skeptical filter let in, and what does it keep out?

In other words, what causes you to have faith?

Many people believe in certain things they have never seen. For example, have you been to Madagascar and seen it with your own eyes? If you haven’t been there, are you sure it exists? Is seeing photos enough to make you believe in its existence? Then what about UFO’s? If you saw a photo of a UFO, would you believe in UFO’s? If not, what’s the difference?

What are you skeptical of, and what do you accept on faith?