First of all what is appreciation. 
Appreciation can be descibe as the act of thanking people before or after helping you. Either with act or by word.
Nowadays many people loose many things because they duppriciate .
Just come to think of it. I gave you what you need for like 3 to 4 month. I you collect it and walk away. Even if you are the owner of the stuff. You don't just have it and walk away on me. That person may not be angry with you but he or she will have it in mind that you don't appreciate and spread the bad new about you.
This may let people dislike you without even knowing you before.
For this it may seize other things from that person to you and other people that know you or not.
No matter how small it is always try to appreciate.
APPRECIATION HAVE MANY ADVANTAGE LIKE
it keep peoples mind good to you
it open new thing (gift) from people to you
it keeps your obidient
appreciation make people spread good new about you
it make people love you more
and many more.
APPRECIATION IS PART OF RUDENESS.
yes. If you are presented a gift or any other things and you don't appreciate it only mean you are rude. May be that person is up to nothing in your view, may be that person is not up to you and many other bad meaning like that.
Before rude to people always remember their going to spread out your good and bad new.
HOW TO APPRECIATE.
if someone give you a gift just accept and say. Thank you for short and a short prayer in his or her presence.
That may be alright but if you want that person to really feel that you appreciate what his or her has done. You have to give that person time.
Example just to discuss about his or her life or you. May a hangout, public service, fun centre, cinema. And so on
Just try to pay that person more attention that's all but if you think you can't do it or that person is not someone you can give your attention just take the gift and say thank you and a short prayer like three to four words.