Staying on Topic: What Can You Ask/Say?
"I saw the Barbie movie this weekend."
ask about the movie, who they went with, if they liked it or not, etc.
"I am so excited for Halloween!"
ask why they are excited, ask why they like Halloween, say if you like Halloween or not, etc.
"My dog hasn't been feeling well lately."
ask what's wrong, say that you hope their dog is ok, ask if there is anything you can do to help, etc.