Have you ever considered taking the time to send in a compliment or two? Whist Marriott is pretty hard to like these days on a corporate level, surely you encounter individual contributors who go above and beyond that you could single out (and in doing so offset your profile as a serial complainer). These days the primary purpose I see for my Ambassador is to channel positive feedback to properties where I've had a really good experience. Also, on the complaining front, I choose my battles very carefully - I want them to hear my roar when I'm truly angry and not just yawn at a song and dance they've seen at least a hundred times before.