I don't get this way of thinking. My mum, when she has done something for someone, expects a massive show of thanks from that person. And if they don't do this she moans and stews about it and holds a grudge. This includes things like if she has her brother to stay for the weekend and she expects to be told how wonderful she is at the end with a gift.
I don't agree with her view on this.
Obviously I do feel that saying thank you is important but I don't think you can expect flowers chocolates and whatever else. And if you do, you are doing it for the wrong reasons imo.