system
surprised: On my 21st birthday my friends threw me a surprise party. A lot of friends from out of town showed up and I was really surprised.
human
For my 21st birthday my friends threw me a surprise party. Friends that I hadn't seen in years showed up, it was great. 
gpt
That sounds so fun. What great friends!
human
Yea I was so shocked, they really came through for me. They are great people!
gpt
I am sure it was a great time!