When we add ‘ed’ to certain verbs, it can be used as an adjective.

It is an emotion or a feeling that the subject is experiencing.

In other words, it is how the subject feels:

• annoy + ‘ed’ = annoyed
  My mother is annoyed.
• amaze + ‘ed = amazed
  My teacher was amazed.
• frustrate + ‘ed’ = frustrated
  She felt frustrated.
• worry + ‘ed’ = worried
  My dad seems worried.
• excite + ‘ed’ = excited
  That dog looks excited.
• confuse + ‘ed’ = confused
  The cat’s face has a confused look.
• surprise = ‘ed’ = surprised
  My friend was surprised.