I don't know actually, I feel so complex. I don't know if you feel that too or I am just the only one who feel this way.
I observed myself that If I already got the thing that I thought I really really want, I always realized in the end that there is something I really want and did not realize it sooner until I've got what I thought I want. :) see, so complicated.
To avoid disappointment and negative feelings, I taught myself to be contented to what I have, feel them and be grateful that I have them. I have to admit that It is really hard to focus on what you have than on what you have not, as a human of course I feel feelings that are humane and normal like those desire to have what you don't have, but may be by continue practicing to always be grateful to little things I have and simply look away from the things I don't have, I think I will be immune to this feeling in the future and not be a too complex person on my own point of view. ^_^