I'd say strange indeed, but not worth a letter. Since the FA was not overtly rude to you or anything, I'd just chalk it up to being a bad/wierd/trying day for her. I know they're not supposed to pass that on to the pax, but to err is to be human. I have also had plenty of FAs be late on picking up service items, as well as plenty who have come around too early for my tastes and have felt rushed to finish up my "whatever". I'd rather have them be late than early. If I'm finished, I usually stuff it in the pocket in the seat ahead of me until they come around.

And if she had told me to see "Anger Management", I probably would have asked her why. Then you'd have your answer, have a chance to tell her you didn't appreciate the comment, or maybe share a laugh because there was a reference that she wasn't passing off to you effectively.