mad

Think of the way a person's face gets all scrunched up when he or she is mad.
This sign doesn't actually touch your face. (That might be painful.)
Mad uses a single motion. If you use a double motion and a slightly less intense face it can mean, "grouchy."

Also see: Angry
Also see: "Angry/Mad advanced discussion."

mad:

Question from a student: "Mad" Is this sign considered to be generally less intense than the sign for "Angry"?

Answer: I think of mad as being less intense than angry, yes. But, I it depends on the usage (body language and facial expression). A person can sign the word "MAD" with very strong facial expression and it will certainly be more intense than a typical version of ANGRY. But I think if you were to work at it, ANGRY could adopt a more intense facial expression and body posture than "MAD."
See: Angry