"it is still nice to be thanked on the PA once in a while..." but why on the PA, why do you need for the thanks to be done so publicly? I can promise you it certainly doesn't go down well if some of the passengers feel they've not had a great flight (Glamgirl's point).
As you've probably guessed I'm another who doesn't like it...I would hope that a good, hard working crew were thanked after the trip by their Captain and/or Cabin "Chief", and I certainly thank the Co-pilots I fly with for looking after me
..but I wouldn't dream of thanking him/her on the PA....IMHO it just sounds crass and just a little bit "luvvy".