and or or surprise

[buran]

What is the surprise for you?

From the docs

The expression x and y first evaluates x; if x is false, its value is returned; otherwise, y is evaluated and the resulting value is returned.

The expression x or y first evaluates x; if x is true, its value is returned; otherwise, y is evaluated and the resulting value is returned.

Also, this part of the docs

Also check Truth Value testing