^People rant that a compliment is BS? I've never heard someone do that, that would be so rude!
Rant is probably not the right word, but (mostly from women) I think it's pretty common. For example when you say "you have really beautiful hair" and get in return "what?! no I don't! My hair is so dirty right now I haven't washed it in like two days, and it's so unhealthy from me bleaching it last month and I have all these split ends..." shut up, please. I obviously do not agree with you or noticed any of those things, so just accept the compliment and try to enjoy it. 8)
I have never understood this opening the door business. I can open the door myself. That said, I do feel obligated to say thank you, so I do. I just find it annoying that we are expected to say "thank you" so many times a day. It has become a hackneyed expression that doesn't really mean much. When I go to the gym and exchange greetings with the person at the desk, She hands my card back and I usually say "Thank you" because it seems to be customary. But what am I rally thanking her for?
When someone actually does something truly generous or kind, it seems that a simple "thank you" would almost be a slight, since we use it all the time for some many lesser things now.
I agree, the door opening business is a bit silly but I think that and a lot of other things that we do are appreciated now not because of their function but because of what they symbolize to us. If someone holds a door open for me, yes, I could have opened that door myself, but it makes me feel good somewhat to see that they care to do it for me---- not that I think me and this person are now going to become best friends or even have a full conversation, but that they chose to do something kind, however small it may be, feel nice.
There are also things that have become traditions that might once have had a function but are now valued for what they symbolize... For example, this may be a bit of a controversial one but I'll use it all the same-- when I go out on a first date, I pretty much expect for the guy to pay. Not at some restaurant where he's going to have to drop a bunch of cash down for my entree, but if we go to a movie or are eating at a moderately inexpensive restaurant, I expect him to pay. Sure, I’ll always bring my wallet with me and offer to split the bill, and I’m not going to argue with the guy if he agrees to do so, but if I have to pay for my meal and my ticket to the movie I’m probably not going to be seeing him again. Stupid? Maybe. Obviously this tradition started when women weren’t expected or really allowed to work many many years ago and so would therefore not have money to pay, and it may bring feminists back 20 years, but for me it’s a sign of respect, appreciation, and care from the guy. (However, if the girl asks the guy to go somewhere, I wouldn’t expect him to be the one to shell out all the money for the evening).
To me thank you is sort of the same as the above—it doesn’t really mean anything, but it’s a sign of respect and so I say to pretty much everyone from the guy who cuts my hair to the person who gives me my change at Starbucks… and when people say it to me for meaningless things it just reinforces that feeling of respect and appreciation.
When someone does something that requires a meaningful thank you, I would say something more along the lines of “Thank you, I really appreciate blank it means a lot.”
So yeah, maybe “thank you” has lost some of it’s meaning, but I don’t think having to articulate a bit more to make it more meaningful is necessarily a bad thing.
I think 'thank you' is a nice custom in our society born out of the good of human nature to express gratitude. What I mean is I don't know why people, who aren't like me and dislike thank you, waste so much time thinking about how much they dislike it. I guess I see your point in that people who don't really mean 'thank you' shouldn't say it as it devalues the genuine gratitude. 
You're great.
