I'm sorry you're feeling unappreciated.
I am 21 and I can tell you my mom feels the exact same way! Atleast she reminds me ALL the time! The problem is since I am the one that lives home still she takes what my brother does, out on me. Today she came to my room and said "I already know that im going to die alone since my 2 kids don't love me or care about me" she says things like this just to get me mad, and she doesn't even know but it hurts my feelings really bad. We might not show our appreciation as much, but it is not out of spite, we just don't notice it most of the time. If my mom would ask me things gently, and nicely i guarantee i will do them, instead of yelling them first thing like she does all the time. So im the kid(well not a kid but you know) and i don't know what to do. I try, yesterday i cleaned the whole house, the dishes, everything and i didn't even get a thank you. When i do things she doesn't seem to 'notice' but when i don't she is quick to yell at me about it. My brother is 25 now and already has his own family. My mom babysits his daughter and most of the time he has an attitude, and my mom gets mad but i know he is very stressed cause he is learning the hard way what it is to hold a household and raise a kid, he works all the time, overtime trying to save money. So i tell her don't take it personally he is just stressed. Sometimes things are not understood and i think that is where the problem is. I would say just try to talk to them gently, ask them if they want to do something with you(something they like) and even though they don't show appreciation i bet they do deep inside. I heard someone say when you are with your parents they annoy you and you want to just get away but when you are away you miss them and feel like a part of you is missing and i think that's true. Seeing you makes them feel better and even though they spent that little bit of time with you it is their way of saying thanks. Am i rambling? lol