Look, I understand exactly where you are coming from. I've been in your position where I felt unappreciated and completely blown off. Really, there are only a couple of things to do about that.
The first is to keep on giving your advice, and when they say no, try to get a more detailed explanation of why. Talk about it. Don't let this fester in the dark. Let them know clearly what you think and, more importantly, why you do.
The second thing is that it seems like you are most definitely frustrated. I hate to say it, but when it is obvious that when someone is frustrated , then the people they approach will not react well, generally speaking. I know this simply because I tried it out at work one day. I spent a while being courteous but not all welcoming and generally just being emotionally cold. It was all business and that hour or so was one of the worst times at work I have ever had. It wasn't fun, it was slow, it was just bad. But when I was being really upbeat, the time went way faster, and was more enjoyable.
As to how I try to be upbeat, I would recommend a video made by Sean "Day[9]" Plott on Being Relentlessly Positive.
http://www.youtube.com/watch?v=iCqwwTfXr1Q