"Don't know what all the fuss is about", "good enough for me" may mean that you have low standards as much as it might mean other people are faffing about needlessly. Perhaps your friends are just being polite and laugh at your cheapskate ways when you're not there.
Mind you, I wouldn't call a friend polite who laughs about someone behind their back, nor a friend, for that matter. I tend to trust people on face value, and I've seen that these sorts of blind studies apparently vary in their success depending on whether the person implementing them claims to have or not have this magical "coffee pallet" as I'll put it. Long and short of things, I don't expect people to be QUITE as backhanded as you suggest, I also don't trust people to do "good science", and I'd need to see a properly empirical study before I made up my mind in either case.