Reciprocated Appreciation

It was my birthday a few days ago, and I don't usually do anything for my birthday except for small get-togethers with various groups of friends/family: I went to see Catching Fire on opening day with my girlfriends from high school, had a family dinner and cake on the actual day, and had lunch with an elementary school friend. But I have a philosophy...You should get treated on your birthday, by your friends and family. It's only logical, because then they get to show you appreciation for your life. At least, that's what I think.
I also think that, if your friends are getting you gifts and you are having a dinner party or something of the sort, you should pay for dinner. (This comes from years of going to other friends' "parties" and paying for my dinner as well as their gifts. I realized that, when we were all younger, we paid for the food and the entertainment, and the presents that your friends brought would somewhat offset the price of the entire affair. As we got older, however, this changed: the individual has to pay for everything.) 
The movie night was fantastic, my friends actually bought me gifts (which they didn't have to do, because I told them they didn't have to) and bought my dinner; I, therefore, didn't let my friends pay for the movie tickets, because I was showing them my appreciation for them. I find that's also fair.
My family is always good to me, and this year was no exception. Sushi for dinner, cream puffs and brownies for dessert, and presents (various items from the frozen yogourt chain, Menchie's, and a pair of [faux?] leather boots).
But then I went to lunch with my friend. And this is the part that irked me for a while yesterday (Friday): I had gone to her birthday earlier in September, and spent $100 dollars on dinner, gifts, and movies, but she didn't even offer to pay for my lunch, which only cost $15. I found this kind of ridiculous. Clearly, I value her more as a friend than she does me.
And this isn't the only time it's happened to me; this is only one of many occurrences. 

Have you had any problems like this? Let me know.