Westwindblows excellent advice, but as tatterdema said, I would extend that to anything and everything. It is always good to read the fine print, aka terms and conditions as they are better known in Marriott parlance, as that is what outlines the rules and benefits of the program.

But we understand you are venting and underneath it all really mentally beating yourself up for not being more knowledgeable. That's OK, welcome to FT, stick around for a while, read some (or a lot) and get knowledgeable, but just be forewarned that it can lead one to being jaded, cynical, and/or a sense of entitlement (all depending on one's perspective).