Anyway, read this from MSN Money. It's pretty accurate, and i guess it's the answer to my spending habits now.

"Constant craving

Economists have coined their own term for this cycle; they call it the "hedonic treadmill", and it works like this:
You really want a new PDA, dining room set, iPod, car, house or whatever.
Finally, after much yearning, you buy the desired item.
You're thrilled for about a week.
The thrill fades.
You start to feel empty and crave that emotional high, the sense of accomplishment or "being good enough."
So you decide that what you REALLY want is a new refrigerator, designer suit, vacation, deck…
And the whole thing starts all over again.
There are several factors that tend to keep people on the hedonic treadmill, and a big one is the tendency to compare your lot with others'. Some researchers have speculated that the human evolutionary drive to compete and survive lingers in our desire to 'keep up' with the material acquisitions of those around us."

But then, except for the idea of purchasing a new phone, the others doesn't quite fit this. Haha... or maybe it's all in the sub-conscious... =p